JP5957533B2 - Measuring apparatus and measuring method - Google Patents

Description

  The present invention relates to a measuring apparatus and a measuring method.

In recent years, an optical time domain reflectometer (sometimes referred to as OTDR) has been used as a means for confirming the line quality of an optical fiber. For example, a method of detecting an optical fiber abnormality by measuring the optical loss of an optical fiber by changing the wavelength of the test light from OTDR and analyzing the wavelength dependence of the optical loss obtained from the measurement result is known. (See Patent Documents 1 to 3).
(Prior art documents)
(Patent Literature)
(Patent Document 1) JP 2011-047914 A (Patent Document 2) JP 2011-038785 A (Patent Document 3) JP 2005-337766 A

  In OTDR, an optical pulse is incident on an optical fiber, and reflected light from the optical fiber is measured in the time domain. Since the signal level of the reflected light is very low, in a series of tests by OTDR, noise is reduced by repeating a plurality of measurements and averaging the measurement results. Therefore, a technique capable of shortening the test time is required.

  According to the first aspect of the present invention, the first optical pulse having the first wavelength and the second optical pulse having the second wavelength are alternately output and incident on the incident end of the optical fiber core wire. Back scattered light from optical fiber output lines and optical fiber core wires corresponding to each of the first optical pulse and the second optical pulse, and back scattered light from a plurality of positions having different distances from the incident end , Measuring an optical demultiplexing unit that demultiplexes the light having the first wavelength and the light having the second wavelength, and the optical power of each of the light having the first wavelength and the light having the second wavelength. A measuring device including a measuring unit is provided.

  According to the second aspect of the present invention, the first optical pulse having the first wavelength and the second optical pulse having the second wavelength are alternately output, and the incident end of the optical fiber core wire to be tested The optical pulse output stage incident on the optical fiber and the back scattered light from the optical fiber core line corresponding to each of the first optical pulse and the second optical pulse, and back from a plurality of positions at different distances from the incident end An optical demultiplexing stage for demultiplexing the scattered light into light having the first wavelength and light having the second wavelength, and respective optical powers of the light having the first wavelength and the light having the second wavelength A measuring method is provided.

  According to the third aspect of the present invention, the measurement device and the information relating to the optical power measured by the measurement device, the rear corresponding to each of the first optical pulse and the second optical pulse. A characteristic determining unit that determines the wavelength-loss characteristics of the optical fiber core wire by using the information on the optical power for each of the scattered light and the wavelength values of the first optical pulse and the second optical pulse; Assuming that the number of turns of the core wire is the first specified value, the optical fiber core wire in the case where the number of turns of the optical fiber core wire is the first specified value using the wavelength versus loss characteristic and the first specified value. And a radius-of-curvature determining unit that determines the radius of curvature of the first portion of the apparatus.

  According to the fourth aspect of the present invention, the measurement device and the information on the optical power measured by the measurement device, the rear corresponding to each of the first optical pulse and the second optical pulse. And a characteristic determining unit that determines the wavelength-loss characteristics of the optical fiber core wire using the information on the optical power of each of the scattered light and the wavelength values of the first optical pulse and the second optical pulse. Assuming that the ratio of the spot sizes of the two optical fiber core wires is the second specified value, the ratio is the second specified value using the wavelength-to-loss characteristic and the second specified value. An apparatus is provided that includes an axis deviation amount determination unit that determines an axis deviation amount of a first portion of the optical fiber core wire.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

An example of the wavelength dependence of the optical loss of the backscattered light of the light which injected into the optical fiber core line is shown roughly. An example of the graph showing the wavelength dependence of the relationship between the radius of curvature [mm] and the macro bending index [dB / nm] when it is assumed that the number of turns is one is shown. An example of the graph showing the wavelength dependence of the relationship between the amount of axis deviation [μm] and the macro bending index [dB / nm] is shown. An example of the abnormality detection apparatus 400 is shown schematically. An example of a method for determining an abnormal amount is schematically shown. An example of the optical power measurement part 410 is shown schematically. An example of the test light 12 of the optical power measurement part 410 is shown schematically. An example of the timing detection unit 656 is schematically shown. An example of the timing detection unit 956 is schematically shown. An example of the timing detection unit 1056 is schematically shown. An example of the optical power measurement part 1110 is shown schematically. An example of the test light 12 of the optical power measurement part 1110 is shown schematically.

  The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Moreover, not all the combinations of features described in the embodiments are essential for the solution means of the invention. In addition, embodiments will be described with reference to the drawings, but in the description of the drawings, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted.

  In this embodiment, first, an apparatus, a method, and a computer for determining at least one of a radius of curvature and an optical axis misalignment amount at an abnormal portion of an optical fiber core wire to be tested using an OTDR that is an example of a measuring apparatus. A readable medium and a program will be described. Thereafter, a configuration of a measuring apparatus capable of outputting two or more optical pulses having different wavelengths will be described. Note that the use of the measuring apparatus according to the present embodiment is not limited to the apparatus and method described in the present embodiment. The measurement apparatus according to the present embodiment may be used for other applications of OTDR that are currently known, or may be used for new applications in which OTDR will be used in the future.

  FIG. 1 schematically shows an example of the wavelength dependence of the optical loss of backscattered light incident on an optical fiber core wire. FIG. 1 shows the measurement result of the optical power of backscattered light from each position of the optical fiber core line obtained using an optical time domain reflectometer (sometimes referred to as OTDR). In FIG. 1, the horizontal axis indicates the distance from the incident end, and the vertical axis indicates the optical power of the backscattered light.

  In the OTDR, test light is incident on an optical fiber core from one end of the optical fiber core (sometimes referred to as an incident end), and back scattered light returns to the incident end from a plurality of positions having different distances from the incident end. Is detected at the incident end. From the time until the backscattered light returns to the incident end after the test light is incident on the incident end, the optical power of the backscattered light at each position of the optical fiber core line can be measured. Thereby, OTDR can acquire the information regarding the optical power of the backscattered light in each position of the optical fiber core wire of the test light incident on the optical fiber core wire.

  The OTDR can acquire information on the optical power of the backscattered light at each position of the optical fiber core wire of the test light incident on the optical fiber core wire for each of a plurality of wavelengths. For example, by performing the measurement a plurality of times while changing the wavelength of the test light, it is possible to acquire the information regarding the optical power for each of the plurality of wavelengths. Moreover, you may acquire the information regarding said optical power about each of several wavelengths by using the test light containing the light of several wavelengths.

  In FIG. 1, a graph 101 shows the optical power of backscattered light that has returned to the incident end when test light having a wavelength of 1550 nm is incident on the optical fiber core line including the portion (a) where an abnormality has occurred. An example of the measurement result is shown. A graph 102 shows an example of a measurement result of the optical power of backscattered light returning to the incident end when test light having a wavelength of 1625 nm is incident on the same optical fiber core wire as the graph 101.

As shown in the graph 101 and the graph 102, the optical power of the backscattered light rapidly decreases at the position (a). On the other hand, at a position other than (a), the optical power of the backscattered light decreases according to the distance from the incident end. The decrease in optical power represents the magnitude of optical loss of the optical fiber core wire. In FIG. 1, L ₁ and L ₂ represent the amount of change in optical power at the position (a) at each wavelength (sometimes referred to as an optical loss amount).

  As shown in FIG. 1, by measuring the optical power of the backscattered light, some abnormality has occurred at the position (a) where the absolute value of the change amount of the optical power per unit distance is rapidly increasing. I understand that. As a cause of an abrupt change in optical power (sometimes referred to as abnormal light loss), a typical example is bending of an optical fiber core and misalignment due to poor fusion connection of the optical fiber core. it can. Creeping can be exemplified as a cause of abnormal bending of the optical fiber core wire. Creeping refers to a phenomenon in which the optical fiber core wire moves in the housing due to vibration or the like, and the optical fiber core wire is bent with a small radius of curvature. Therefore, abnormal light loss often occurs in an optical connection portion of the optical fiber core wire and a housing portion (sometimes referred to as a closure portion) that accommodates the extra length of the optical fiber core wire.

  By using the graph 101 and the graph 102, for example, it can be inferred that some abnormality has occurred in the accommodating portion in the vicinity of the position (a). However, from the graph 101 and the graph 102, the cause or type of abnormality at the position (a) cannot be specified. In addition, the degree of abnormality at position (a) cannot be grasped.

On the other hand, Patent Document 1 uses the fact that the wavelength dependency of the optical loss amount due to bending is larger than the wavelength dependency of the optical loss amount due to axial deviation, and abnormal bending occurs in the optical fiber core wire. A method for identifying the location is described. Specifically, first, for each of two lights having different wavelengths, the optical power of the backscattered light is measured using OTDR, and a location where an abnormal light loss occurs is specified. Next, the macro bending index k _macro at the location where the abnormal light loss occurs is calculated. Then, when the macro bending index k _macro is larger than a predetermined reference value, it is determined that the abnormal light loss at the portion is due to the abnormal bending, so that the abnormal bending occurs in the optical fiber core wire. The location is specified.

Here, the macro bending index k _macro can be calculated by the following equation (1).
k _macro = {Loss (λ ₂ ) −Loss (λ ₁ )} / (λ ₂ −λ ₁ ) (Formula 1)
In Equation 1, λ ₁ and λ ₂ represent the wavelength [nm] of the test light that is incident on the optical fiber core wire and the optical power of the backscattered light is measured. Note that λ ₂ > λ ₁ is preferable. Loss (λ ₁ ) represents the amount of light loss [dB] at a specific location of the optical fiber core wire when the wavelength of the test light is λ ₁ . Loss (λ ₂ ) represents the amount of light loss [dB] at a specific location of the optical fiber core wire when the wavelength of the test light is λ ₂ .

The macro bending index k _macro represents the slope of the wavelength versus loss characteristic. The wavelength versus loss characteristic indicates the relationship between a plurality of wavelengths and the amount of change in optical power at a specific location of the optical fiber core wire at each of the plurality of wavelengths. The wavelength versus loss characteristic represents the wavelength dependence of the amount of change in optical power at a specific location of the optical fiber core wire. The wavelength-to-loss characteristics are, for example, the wavelength value obtained by measuring the optical power of the backscattered light with the horizontal axis representing the wavelength, and the vertical axis representing the amount of change in the optical power at a specific position of the optical fiber core line, and the optical power at the wavelength. It can be determined by plotting the relationship with the amount of change. The method for determining the wavelength-to-loss characteristic is not particularly limited as long as it is a method that can acquire the correspondence between each of a plurality of wavelengths and the amount of change in optical power at each wavelength. Moreover, said specific location may be an example of a 1st location.

  According to the method described in Patent Document 1, it is possible to determine whether or not an abnormal bending has occurred in the optical fiber core wire at the position (a). However, it is difficult to intuitively grasp the degree of abnormality at the position (a).

If the value of the macro bending index k _macro is positive according to the subsequent research, it may be determined that an abnormal bending has occurred in the optical fiber core wire, and the value of the macro bending index k _macro is negative. It has been found that it is possible to determine that an axis deviation has occurred due to poor fusion splicing. Therefore, the present inventors examined an apparatus, a method, and a program for grasping the degree of abnormality at the position (a) using the wavelength-loss characteristic.

As a method of grasping the degree of bending of the optical fiber core wire at the position (a) using the wavelength versus loss characteristic, for each of the optical fiber core wires to be measured, the macro bending index k _macro and the bending radius of curvature are calculated. It is conceivable to obtain the relationship in advance. In addition, as a method of grasping the degree of axial deviation of the optical fiber core line at the position (a) using the wavelength vs. loss characteristic, the macro bending index k _macro and the axial deviation amount are measured for each optical fiber core line to be measured. It is conceivable to obtain a relationship with

Thereby, by determining the macro bending index k _macro , it is possible to determine the radius of curvature and the amount of axial deviation based on the relationship obtained in advance. In particular, since the macro bending index k _macro can be determined by measurement at one end of the optical fiber core wire, it is easy to analyze an abnormality of the optical fiber core wire.

However, the wavelength of a semiconductor laser mounted on an actual OTDR has a large individual difference due to OTDR, and an individual difference of about ± 20% may occur. Since the macro bending index k _macro depends on the measurement wavelength, according to the above method, each time the OTDR is changed, the above relationship is determined for each of the optical fiber core wires, which is very complicated. .

  Therefore, the present inventors have noted that there are few cases where the optical fiber core wire is wound many times in the case where the abnormal bending is actually generated in the optical fiber core wire. As a result, assuming that the number of turns of the optical fiber is the first specified value, the radius of curvature (imaginary) of the first portion of the optical fiber core when the number of turns of the optical fiber core is the first specified value. In this case, the technical idea of grasping the degree of bending of the optical fiber core wire has been conceived.

  In reality, focusing on the fact that the spot sizes of the two optical fiber core wires to be connected are substantially equal, the ratio of the spot sizes of the two optical fiber core wires to be connected at the first location of the optical fiber core wire is Assuming that the ratio is the second specified value, assuming that the ratio is the second specified value, the amount of axial misalignment at the first location of the optical fiber core wire (sometimes referred to as a virtual misalignment amount). As a result, the technical idea of grasping the degree of axial misalignment of the optical fiber core wire was conceived.

(Virtual radius of curvature)
FIG. 2 shows an example of a graph representing the wavelength dependence of the relationship between the radius of curvature R [mm] and the macro bending index k _macro [dB / nm] when it is assumed that the number of turns is one. An example of an embodiment for grasping the degree of bending of an optical fiber core wire using a virtual radius of curvature will be described with reference to FIG. In the present embodiment, a case will be described in which the relationship between the measurement wavelengths λ ₁ and λ ₂ in OTDR, the macro bending index k _macro, and the virtual curvature radius R is calculated in advance.

FIG. 2 shows a calculation result of the macro bending index k _macro when the first wavelength λ ₁ and the number of turns are fixed to 1310 nm and one rotation, respectively, and the radius of curvature R and the second wavelength λ ₂ are changed variously. Indicates. The macro bending index k _macro was calculated using the value of K determined by the equation (9) described later. In FIG. 2, a graph 201, a graph 202, a graph 203, a graph 204, a graph 205, a graph 206, a graph 207, a graph 208, a graph 209, a graph 210, and a graph 211 have a curvature radius R of 5 mm, 6 mm, 7 mm, respectively. Calculation results for 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, and 15 mm are shown.

In the present embodiment, the degree of bending of the optical fiber core wire can be grasped by the following procedure. First, for example, the optical power of backscattered light at wavelengths of 1310 nm and 1500 nm is measured using OTDR. Next, the macro bending index k _macro is determined using the measurement result and the value of the measurement wavelength. If the determined macro bending index k _macro is positive, it is determined that an abnormality due to bending has occurred in the optical fiber core wire. When the value of the determined macro bending index k _macro is, for example, 0.005 [dB / nm], from FIG. 2, the hypothetical curvature radius when the number of turns is assumed to be 1 rotation is 8 mm. It can be determined that there is. When the value of the macro bending index k _macro is 0.010 [dB / nm], the virtual radius of curvature when the number of turns is assumed to be 1 rotation is between 7 mm and 8 mm. Can be determined.

Since the macro bending index k _macro is an example of the slope of the wavelength vs. loss characteristic, as shown in FIG. 2, assuming that the number of turns n of the optical fiber core wire is the first specified value, the wavelength vs. loss characteristic is obtained. Can be used to determine a virtual radius of curvature. By determining the value of the virtual radius of curvature, it is possible to intuitively grasp the degree of bending of the optical fiber core wire, and to easily evaluate the abnormality of the optical fiber core wire. The number of turns n of the optical fiber is not limited to 1. The number of turns n of the optical fiber may be a value between 0 and 1.

According to the present embodiment, even when the OTDR is changed, the information on the optical power of the backscattered light in each of the measurement wavelengths λ ₁ and λ ₂ and the measurement wavelengths λ ₁ and λ ₂ by the OTDR Can be used to determine the degree of bending of the optical fiber core wire. Note that, even if the actual measurement wavelength λ ₁ is different from the first wavelength used in the calculation of the relationship in FIG. 2 due to individual differences in OTDR, the approximate degree of bending can be determined. Further, as shown in FIG. 2, the virtual curvature radius can be determined more accurately as the wavelength difference between the _two measurement wavelengths λ ₁ and λ ₂ is larger.

In the present embodiment, the case where the measurement wavelengths λ ₁ and λ ₂ in OTDR, the macro bending index k _macro and the virtual curvature radius R are calculated in advance has been described. However, the method of grasping the degree of bending of the optical fiber core wire using the virtual curvature radius is not limited to this. Using the measurement wavelengths λ ₁ and λ ₂ in OTDR and the measurement result of OTDR, for example, a virtual radius of curvature may be calculated by the following procedure.

In the present embodiment, first, the relationship between the light loss amount Loss _bend (λ) of light of wavelength λ and the curvature radius R of the bending of the optical fiber core wire is determined. For example, when the optical fiber core wire is a single mode optical fiber, the optical loss amount Loss _bend (λ) of light of wavelength λ when the optical fiber core wire is rotated n while drawing a curve with a radius of curvature R is as follows: It can be determined using equation (2).

In Expression (2), α (λ), A (λ), and B (λ) are expressed by using the following Expression (3), Expression (4), and Expression (5), respectively, from the Marcus expression. (For details, see D. Marcuse, “Curvature loss formula for optical fibers,” Journal of Optical Society of America, Vol. 66, No. 3, pp. 216-220, 1976.)

In Expressions (3) to (5), β _g represents a propagation constant, and K ₁ represents a modified Bessel function. К, γ, and V can be expressed using the following formulas (6), (7), and (8), respectively. Note that κ, γ, and V are functions of λ, but for the purpose of simplifying the expression, к (λ) may be expressed as к, γ (λ) as γ, and V (λ) as V in some cases.

In the formula (6) to Formula (8), n ₁ represents the refractive index of the core of the optical fiber core, n ₂ represents the refractive index of the cladding of the optical fiber core. k represents a wave number, and k = 2π / λ. a represents the core radius of the optical fiber core wire.

Then, when the wavelength is lambda ₂ and the light loss _{Loss bend} (λ _2), the difference K between the optical loss _{Loss bend} (λ ₁₎ when the wavelength is lambda _1, the radius of curvature R Determine the relationship. Difference K of the present embodiment, the optical loss _{Loss bend} when the wavelength is λ ₂ (λ _2), the optical loss _{Loss bend} (λ ₁₎ when the wavelength is lambda _1, the following formula It can be determined by (9).

  Next, among the elements included in the relational expression between K and R, among the elements that cannot be uniquely determined from the measurement conditions and measurement results of measurement using OTDR, elements other than the curvature radius R are specified. The radius of curvature R is determined on the assumption that it is a value of (which may be referred to as a prescribed value). In the present embodiment, among the elements included in Equation (9), elements other than the winding number n and the radius of curvature R can be uniquely determined from the measurement conditions and measurement results of the measurement using OTDR. Therefore, the radius of curvature R can be determined by assuming that the number of turns n is a specified value. Thereby, the virtual curvature radius R can be determined.

In the present embodiment, the case where the relationship between the light loss amount Loss _bend (λ) of the light of wavelength λ in the single-mode optical fiber and the curvature radius R is derived using the Marcuse equation has been described. However, the method of deriving the relationship between the light loss amount Loss _bend (λ) and the radius of curvature R is not limited to this. As another example, the relationship may be derived based on at least one of other theoretical formulas, empirical formulas, and empirical formulas.

  In the present embodiment, the case has been described in which the virtual curvature radius that can be used for the evaluation of abnormality is determined on the assumption that the number of turns of the optical fiber core wire is the first specified value. However, the method for determining the virtual curvature radius is not limited to this. Among the elements included in other theoretical formulas, empirical formulas, or empirical formulas in the other examples described above, one or more elements other than the curvature radius R among the elements that cannot be uniquely determined from the measurement conditions and the measurement results May be determined on the assumption that each is a specified value corresponding thereto. By setting the value of one or more elements other than the curvature radius R to an appropriate value, it is possible to intuitively grasp the degree of bending of the optical fiber core wire from the determined virtual curvature radius value.

(Virtual axis deviation)
FIG. 3 shows an example of a graph representing the wavelength dependence of the relationship between the axis deviation d [μm] and the macro bending index [dB / nm]. With reference to FIG. 3, an example of an embodiment that grasps the degree of axial misalignment of the optical fiber core wire using a virtual misalignment amount will be described. In the present embodiment, a case will be described in which the relationship between the measurement wavelengths λ ₁ and λ ₂ in OTDR, the macro bending index k _macro, and the virtual axis deviation amount d is calculated in advance.

FIG. 3 shows the macro bending index k _macro according to the equations (1) and (15) when the first wavelength λ1 is fixed at 1310 nm and the amount of misalignment d and the second wavelength λ2 are changed variously. The calculation result of is shown. Assuming that the ratio of the spot sizes w ₁ and w ₂ of the _two optical fiber core wires to be connected is 1, the macro bending index k _macro is calculated using the value of K determined by the equation (16) described later. Calculated. In FIG. 3, graph 301, graph 302, graph 303, graph 304, and graph 305 show calculation results when the axis deviation amount d is 1 μm, 2 μm, 3 μm, 4 μm, and 5 μm, respectively.

In the present embodiment, the degree of axial misalignment of the optical fiber core wire can be grasped by the following procedure. First, for example, the measurement of the optical power of backscattered light at wavelengths of 1310 nm and 1500 nm is measured using OTDR. Next, the macro bending index k _macro is determined using the measurement result and the value of the measurement wavelength. If the determined value of the macro bending index k _macro is negative, it is determined that an abnormality due to the axis deviation has occurred in the optical fiber core wire. When the determined value of the macro bending index k _macro is, for example, −0.005 [dB / nm], the ratio of the spot sizes w ₁ and w ₂ of the two connected optical fiber cores from FIG. It is possible to determine that the virtual axis deviation amount is 5 μm when it is assumed that 1 is 1.

Since the macro bending index k _macro is an example of the slope of the wavelength versus loss characteristic, as shown in FIG. 3, the ratio of the spot sizes w ₁ and w ₂ of the two optical fiber core wires to be connected is the second specified value. As a result, it is possible to determine a virtual axis deviation amount using the wavelength-loss characteristic. By determining the value of the virtual axis deviation amount, the degree of axis deviation of the optical fiber core line can be intuitively grasped, and the abnormality of the optical fiber core line can be easily evaluated.

The ratio of the spot size w ₁ and w ₂ of the two optical fiber cores to be connected is not limited to 1. The ratio between the spot sizes w ₁ and w ₂ of the _two optical fiber core wires to be connected may be different for each wavelength. However, in an actual transmission line, the production lots of two optical fiber core wires to be connected are often the same. In particular, when the optical fiber core wire is a single mode optical fiber, generally, the characteristics of the optical fiber core wire are substantially the same. Therefore, by assuming that the ratio of the spot sizes w ₁ and w ₂ of the two connected optical fiber core wires is 1, the actual situation can be reproduced better. As a result, it becomes easy to intuitively grasp the degree of axial deviation of the optical fiber core wire from the determined value of the virtual axial deviation.

According to the present embodiment, even when the OTDR is changed, the information on the optical power of the backscattered light in each of the measurement wavelengths λ ₁ and λ ₂ and the measurement wavelengths λ ₁ and λ ₂ by the OTDR Can be used to determine the degree of axial misalignment of the optical fiber core wire. Note that, even if the actual measurement wavelength λ ₁ is different from the first wavelength used in the calculation of the relationship in FIG. 3 due to the individual difference of OTDR, the approximate degree of axial deviation can be determined. . In addition, as shown in FIG. 3, it can be seen that the absolute value of the macro bending index k _macro in FIG. 3 is smaller than that in FIG.

In the present embodiment, the case where the measurement wavelengths λ ₁ and λ ₂ in OTDR, the macro bending index k _macro, and the virtual axis deviation amount d are calculated in advance has been described. However, the method of grasping the degree of the axial deviation of the optical fiber core wire using the virtual axial deviation amount is not limited to this. Similarly to the case of the virtual curvature radius, the virtual axis deviation amount may be calculated by the following procedure, for example, using the measurement wavelengths λ ₁ and λ ₂ in OTDR and the measurement result of OTDR. .

In the present embodiment, first, the relationship between the light loss amount Los _splice (λ) of light of wavelength λ and the axis deviation d of the optical fiber core wire is determined. For example, when the optical fiber core wire is a single mode optical fiber, the optical loss amount Loss _splice (λ) of the light of the wavelength λ when the two optical fiber core wires are offset by the axis offset amount d is as follows: It can be determined using equation (10).
Loss _splice (λ) = − ₁₀ log ₁₀ (Td) Equation (10)

In Equation (10), T _d can be expressed using the following Equation (11) from the Marcus equation (for details, see D. Marcuse, “Loss analysis of single-mode fiber splices,” Bell System (See Technical Journal, Vol. 56, No. 5, pp. 703-718, 1977.)

In the formula (11), _{w 1} and _{w 2} are the spot size of the two optical fiber cores to be connected. In the formula (11), D can be expressed using the following formula (12). In the formula (11), C can be expressed using the following formula (13). As shown in Expression (13), it can be seen that C has a value corresponding to the ratio of the spot sizes w ₁ and w ₂ regardless of λ. Note that Td, w ₁ , w ₂ , C, and D are functions of λ, but for the purpose of simplifying expression, Td (λ) is Td, w ₁ (λ) is w ₁ , w ₂ (λ). May be represented as w ₂ , C (λ) as C, and D (λ) as D.

The spot size of the optical fiber core wire is defined as a half of MFD (Mode Field Diameter). MFD can be expressed using the following formula (14). In Expression (14), a is the core radius of the optical fiber core line as described above, and V is expressed using Expression (8) above (for details, see D. Marcuse, “Loss analysis of single-mode. fiber splices, "Bell System Technical Journal, Vol. 56, No. 5, pp. 703-718, 1977.).

Here, when it is assumed that the ratio of the spot sizes w ₁ and w ₂ is 1, the light loss amount Loss _splice (λ) of the light with the wavelength λ is determined using the following equation (15). Can do.
Loss _splice (λ) = 4.343d ² D (λ) Equation (15)

Therefore, an optical loss _{Loss's splice} cases wavelength is lambda ₂ (lambda _2), the difference K between the optical loss _{Loss's splice} (lambda ₁₎ when the wavelength is lambda _1, the following equation (16) Can be determined by. In Expression (16), elements other than the axis deviation amount d can be uniquely determined from measurement conditions and measurement results of measurement using OTDR.

In the present embodiment, the case where the relationship between the optical loss amount Loss _splice (λ) of the light of wavelength λ in the single-mode optical fiber and the axis deviation amount d is derived using the Marcuse equation has been described. However, the method of deriving the relationship between the optical loss amount Loss _splice (λ) and the axis deviation amount d is not limited to this. As another example, the relationship may be derived based on at least one of other theoretical formulas, empirical formulas, and empirical formulas.

In the present embodiment, it is assumed that the ratio of the spot sizes w ₁ and w ₂ of the two optical fiber core wires to be connected is the second specified value, and can be used for abnormality evaluation. The case where the amount of axis deviation is determined has been described. However, the method for determining the virtual axis deviation amount is not limited to this. The ratio of the spot size w ₁ and w ₂ of the two optical fiber cores to be connected may be a different value for each wavelength. That is, the second specified value may be a constant value that does not depend on the wavelength, or may be a value that is determined according to the wavelength. Also, the values of the spot sizes w ₁ and w _{2 at} the wavelength λ are substituted by substituting the physical property values and the wavelength λ of the two optical fiber core wires to be connected into the expressions (8) and (14). May be determined.

  Furthermore, among the elements included in other theoretical formulas, empirical formulas, or empirical formulas in the above other examples, among the elements that cannot be uniquely determined from the measurement conditions and measurement results, 1 other than the axis deviation amount d The virtual axis deviation amount may be determined on the assumption that the above elements are the corresponding specified values. By intuitively grasping the degree of axial deviation of the optical fiber core wire from the determined virtual axis deviation value by setting the value of one or more elements other than the axis deviation d to an appropriate value Can do.

When the spot sizes w ₁ and w _{2 at} a specific wavelength λ can be determined by an empirical formula or an empirical formula, the spot sizes w ₁ and w ₂ determined from the empirical formula or the empirical formula are determined. The axis deviation amount d may be determined using the value. Alternatively, the spot size w ₁ and w ₂ may be actually measured, and the axis deviation amount d may be determined using a value obtained by actual measurement.

  FIG. 4 schematically shows an example of the abnormality detection apparatus 400. The abnormality detection device 400 measures the amount of light loss at a plurality of positions of the optical fiber core wire, and determines a location where an abnormality has occurred in the optical fiber core wire. In the present embodiment, the abnormality detection device 400 includes an optical power measurement unit 410, an abnormal part specifying unit 420, an abnormal amount determination unit 430, and an optical fiber core wire database 440. The abnormal amount determination unit 430 includes a characteristic determination unit 432, a determination unit 434, a curvature radius determination unit 436, and an axis deviation amount determination unit 438. The abnormality detection device 400 and the optical power measurement unit 410 may be an example of a measurement device. The abnormality detection device 400 and the abnormal amount determination unit 430 may be examples of devices.

  The optical power measurement unit 410 measures the optical power of light passing through at least a part of the optical fiber core wire. In the present embodiment, the optical power measurement unit 410 makes test light incident on the optical fiber core wire from one end of the optical fiber core wire. Further, the optical power measurement unit 410 measures the optical power of the backscattered light returning toward the incident end from a plurality of positions having different distances from the incident end. Thereby, the information regarding the optical power of the backscattered light from the several position from which the distance from the incident end of the light which entered from the incident end of the optical fiber core wire differs can be acquired.

  The optical power measurement unit 410 may measure the optical power of backscattered light for a plurality of wavelengths. Thereby, the information regarding said optical power about each of a some wavelength is acquirable. The optical power of the backscattered light may be measured at the incident end. The amount of change in optical power measured by the optical power measurement unit 410 indicates the amount of light loss at each location of the optical fiber core wire. The optical power measurement unit 410 may be an OTDR.

  In the present embodiment, the optical power measurement unit 410 outputs information on optical power to the abnormal part specifying unit 420, the abnormal amount determination unit 430, the curvature radius determination unit 436, and the axis deviation amount determination unit 438. Information on optical power includes at least identification information for identifying an optical fiber core wire to be measured, information on wavelengths used for measurement, and optical power of backscattered light from a plurality of positions of the optical fiber core wire. One may be included.

  The abnormal part specifying unit 420 specifies an abnormal part in which an optical loss larger than a predetermined optical loss amount occurs. In the present embodiment, the abnormal part specifying unit 420 receives the optical power of backscattered light from a plurality of positions from the optical power measuring unit 410. The abnormal part specifying unit 420 outputs the specified abnormal part to the characteristic determining unit 432.

  In the present embodiment, the abnormal part specifying unit 420 determines the amount of change in optical power per unit distance at each position based on the received optical power at each of the plurality of positions. When the absolute value of the amount of change in optical power per unit distance is equal to or greater than a predetermined value, the abnormal location specifying unit 420 specifies the location as an abnormal location. Thereby, the location where the optical power has changed abruptly can be identified as an abnormal location.

  The abnormal part specifying unit 420 may specify a part where the absolute value of the change amount of the optical power is abruptly changed as an abnormal part. The abnormal part specifying unit 420 may detect a part where the absolute value of the change amount of the optical power has rapidly increased and specify the part as an abnormal part. The abnormal part specifying unit 420 may correct the distance to the position where the backscattered light is generated by a known method. For example, the abnormal location specifying unit 420 corrects the distance to the position where the backscattered light of at least one of the plurality of wavelengths is generated using the chromatic dispersion value or group delay of at least one of the plurality of wavelengths. be able to.

  The abnormal amount determination unit 430 determines an abnormal amount that is an index indicating the degree of abnormality at a specific location of the optical fiber core wire. Examples of the abnormal amount include a radius of curvature indicating the degree of bending of the optical fiber core wire or an amount similar thereto, or an axis deviation amount indicating the degree of axial deviation of the optical fiber core wire or an amount similar thereto.

In the present embodiment, the abnormal amount determination unit 430 acquires information regarding the optical power of the backscattered light of the optical fiber core wire to be measured from the optical power measurement unit 410. The abnormal amount determination unit 430 acquires information on the position of the abnormal part from the abnormal part specifying unit 420. The abnormal amount determination unit 430 acquires information used to determine the abnormal amount from the optical fiber core line database. Information used for determining the abnormal amount includes the type of optical fiber core, propagation constant β _g , refractive index n _{1 of} the core of the optical fiber core, refractive index n ₂ of the cladding of the optical fiber core, core radius a of the optical fiber core, And at least one of the values of spot sizes w ₁ and w ₂ at one or more wavelengths may be included.

  In the present embodiment, the abnormal amount determination unit 430 includes a curvature radius determination unit 436 and an axis deviation amount determination unit 438, and the virtual curvature radius and the virtual axis deviation described with reference to FIGS. A case where the amount is determined will be described. However, the abnormal amount determination unit 430 is not limited to this. The abnormal amount determination unit 430 may include one of the curvature radius determination unit 436 and the axis deviation amount determination unit 438, and may determine one of the virtual curvature radius and the virtual axis deviation amount.

  The characteristic determination unit 432 measures a plurality of wavelengths obtained by measuring the optical power of the backscattered light from a plurality of positions at different distances from the incident end of the light incident from the incident end of the optical fiber core wire, regarding the plurality of wavelengths. The wavelength-loss characteristics of the optical fiber core line are determined using the information regarding the optical power and the values of the plurality of wavelengths. The characteristic determining unit 432 may determine the slope of the wavelength versus loss characteristic.

  In the present embodiment, the characteristic determination unit 432 acquires information on the optical power of the backscattered light from the optical fiber core wire to be measured from the optical power measurement unit 410. The characteristic determination unit 432 acquires information regarding the position of the abnormal part from the abnormal part specifying unit 420. The characteristic determination unit 432 outputs to the determination unit 434 the wavelength versus loss characteristic of the optical fiber core wire at the abnormal location. The characteristic determination unit 432 may output to the determination unit 434 the slope of the wavelength versus loss characteristic of the optical fiber core wire at the abnormal location.

  In the present embodiment, the characteristic determination unit 432 uses the optical power for each of the plurality of wavelengths measured by the optical power measurement unit 410 and the values of the plurality of wavelengths used for the measurement to determine the wavelength of the optical fiber core wire. Determine loss-to-loss characteristics. Specifically, the characteristic determining unit 432 determines the wavelength versus loss characteristic at the abnormal location based on the relationship between the values of the plurality of wavelengths and the amount of change in optical power at the abnormal location for each of the plurality of wavelengths. To do.

  The characteristic determination unit 432 may determine the wavelength-loss characteristics at each abnormal location when there are a plurality of abnormal locations. The characteristic determination unit 432 uses the values of the two wavelengths and the amount of change in the optical power at the abnormal part for each of the two wavelengths, based on the equation (1), to determine the wavelength versus loss characteristic at the abnormal part. The slope may be determined. The characteristic determination unit 432 uses an appropriate approximation method (for example, the least square method) based on the three or more wavelengths and the change amount of the optical power at the abnormal portion for each of the three or more wavelengths. The slope of the wavelength versus loss characteristic may be determined.

  The determination unit 434 determines whether the slope of the wavelength versus loss characteristic is equal to the third specified value or greater than the third specified value. In the present embodiment, the determination unit 434 determines whether the slope of the wavelength versus loss characteristic is equal to the third specified value or greater than the third specified value, and determines the abnormal amount determination unit 430. The type of abnormal amount to be determined in is determined.

  In the present embodiment, the determination unit 434 acquires the wavelength versus loss characteristic and the slope of the wavelength versus loss characteristic at the abnormal location from the characteristic determination unit 432. The determination unit 434 outputs an instruction for determining an abnormal amount to one of the curvature radius determination unit 436 and the axis deviation amount determination unit 438. The determination unit 434 may output the wavelength versus loss characteristic at the abnormal location together with the above instruction.

In the present embodiment, the determination unit 434 determines whether or not the macro bending index k _macro obtained using Equation (1) is greater than zero. When the macro bending index k _macro determined using the equation (1) is greater than 0, the determination unit 434 has described the curvature radius determination unit 436 with reference to FIG. An instruction for determining a virtual radius of curvature is output. In the present embodiment, the determination unit 434 determines whether or not the macro bending index obtained using Expression (1) is smaller than zero. When the macro bending index k _macro determined using the equation (1) is smaller than 0, the determination unit 434 explains the axis deviation amount determination unit 438 in relation to FIG. An instruction for determining the virtual axis deviation amount is output.

  The curvature radius determination unit 436 determines the degree of bending at the abnormal portion of the optical fiber core wire. The radius-of-curvature determining unit 436 assumes that the number of turns of the optical fiber core wire is the first specified value, and uses the wavelength versus loss characteristic and the first specified value to set the number of turns of the optical fiber core wire to the first value. The radius of curvature is determined when the value is the specified value.

  In the present embodiment, the curvature radius determination unit 436 receives an instruction from the determination unit 434 to determine the curvature radius. Thereby, the curvature radius determination unit 436 determines the curvature radius when the slope of the wavelength versus loss characteristic is equal to or greater than the third specified value. At this time, the radius-of-curvature determination unit 436 may receive the wavelength versus loss characteristic at the abnormal location from the determination unit 434.

  In the present embodiment, the curvature radius determination unit 436 receives information regarding optical power from the optical power measurement unit 410. The information regarding the optical power may include identification information for identifying the optical fiber core wire to be measured and information regarding the wavelength used for the measurement. The curvature radius determination unit 436 outputs identification information for identifying the optical fiber core wire to the optical fiber core wire database 440. The curvature radius determination unit 436 obtains information associated with the identification information from the optical fiber core database 440 and used for determining the curvature radius.

For example, the radius-of-curvature determination unit 436 determines the propagation constant β _g , the refractive index n _{1 of} the core of the optical fiber core line, the refractive index n ₂ of the cladding of the optical fiber core line, and the core radius a of the optical fiber core line from the optical fiber core line database 440. To get. Next, using the acquired information, the radius of curvature when the number of turns is assumed to be a specific number is determined based on Equation (9). The curvature radius determination unit 436 may determine the curvature radius on the assumption that the number of turns is 1. The curvature radius determination unit 436 outputs the determined curvature radius as an index for grasping the degree of bending. By appropriately setting the value of the number of windings, an intuitively easy-to-understand index can be provided.

  The axis deviation amount determination unit 438 determines the degree of axis deviation at the abnormal location of the optical fiber core wire. Assuming that the ratio of the spot sizes of the two optical fiber core wires to be connected is the second specified value, the axis deviation amount determining unit 438 uses the wavelength-to-loss characteristic and the second specified value to calculate the ratio. Determines the amount of axial misalignment of the first portion of the optical fiber core wire when is the second specified value.

  In the present embodiment, the axis deviation amount determination unit 438 receives an instruction from the determination unit 434 to determine the axis deviation amount. Thereby, the axis deviation amount determination unit 438 determines the axis deviation amount when the slope of the wavelength versus loss characteristic is equal to or smaller than the third prescribed value. At this time, the axis deviation determination unit 438 may receive the wavelength versus loss characteristic at the abnormal location from the determination unit 434.

  In the present embodiment, the axis deviation amount determination unit 438 receives information regarding optical power from the optical power measurement unit 410. The information regarding the optical power may include identification information for identifying the optical fiber core wire to be measured and information regarding the wavelength used for the measurement. The curvature radius determination unit 436 outputs identification information for identifying the optical fiber core wire to the optical fiber core wire database 440. The axis deviation amount determination unit 438 acquires information that is associated with the identification information from the optical fiber core database 440 and is used for determining the axis deviation amount.

For example, the axis deviation determination unit 438 obtains the refractive index n _{1 of} the core of the optical fiber core line, the refractive index n ₂ of the cladding of the optical fiber core line, and the core radius a of the optical fiber core line from the optical fiber core line database 440. Based on the equation (15), the amount of axial deviation is determined when it is assumed that the ratio of the spot sizes of the two optical fiber core wires to be connected is a specific value. The axis deviation amount determination unit 438 may determine the axis deviation amount assuming that the ratio is 1. The axis deviation amount determination unit 438 outputs the determined axis deviation amount as an index for grasping the degree of axis deviation. By appropriately setting the value of the above ratio, an intuitively easy-to-understand index can be provided.

The optical fiber core line database 440 stores optical fiber core line identification information and information used for determining an abnormal amount in association with each other. Information used for determining the abnormal amount includes the type of optical fiber core, propagation constant β _g , refractive index n _{1 of} the core of the optical fiber core, refractive index n ₂ of the cladding of the optical fiber core, core radius a of the optical fiber core, And at least one of the values of spot sizes w ₁ and w ₂ at one or more wavelengths may be included.

  The optical fiber core database 440 may be a storage device or storage medium such as a hard disk, a CD-ROM, an IC card, or a flash memory. The optical fiber core line database 440 may be a virtualized or cloud storage device or storage medium. The optical fiber core database 440 may be a memory such as a ROM, a RAM, or a cache memory.

  Each part of the abnormality detection device 400 and the abnormality detection device 400 may be realized by hardware, may be realized by software, or may be realized by a combination of hardware and software. The abnormality detection device 400 may be a system specialized for each application, or a general-purpose information processing device such as a personal computer. The specialized system and information processing apparatus described above may be configured by a single computer or may be configured by a plurality of computers distributed on a network.

  The computer may function as the abnormality detection device 400 or a part of the abnormality detection device 400 by executing the program. The program may be stored in a computer-readable medium, or may be stored in a storage device connected to a network. In an information processing apparatus having a general configuration including a data processing device having a CPU, ROM, RAM, communication interface, etc., an input device, an output device, and a storage device, the operation of each part of the abnormality detection device 400 is defined. The abnormality detection device 400 may be realized by starting the software or program. A program that is installed in a computer and causes the computer to function as part of the abnormality detection device 400 or the abnormality detection device 400 according to the present embodiment includes a module that defines the operation of each part of the abnormality detection device 400 or the abnormality detection device 400. These programs or modules work on the CPU or the like to cause the computer to function as the abnormality detection device 400 or each part of the abnormality detection device 400, respectively. Information processing described in these programs functions as a specific means in which software and the various hardware resources described above cooperate with each other by being read by a computer. A specific measurement device according to the purpose of use can be constructed by realizing calculation or processing of information according to the purpose of use of the computer in the present embodiment by these specific means.

  Each part of the abnormality detection device 400 may execute a part of each other's function. For example, the curvature radius determination unit 436 and the axis deviation amount determination unit 438 may execute part or all of the processing in the determination unit 434 described in the present embodiment. In addition, the optical power measurement unit 410 may execute part or all of the processing in at least one of the characteristic determination unit 432 and the abnormal part identification unit 420 described in the present embodiment.

  FIG. 5 schematically shows an example of an abnormality amount determination method in the abnormality detection apparatus 400. In this embodiment, in step 502 (the step may be referred to as S), for a plurality of wavelengths, rearward from a plurality of positions at different distances from the incident end of the light incident from the incident end of the optical fiber core wire. Measure the optical power of the scattered light. The optical power measurement may be performed by the optical power measurement unit 410. Thereby, the information regarding the optical power about each of a some wavelength is acquirable.

  In S504, using the information about the optical power, a part where a light loss larger than a predetermined light loss amount is identified as an abnormal part. For example, first, based on the optical power at each of a plurality of positions, the amount of change in optical power per unit distance at each position is determined. Next, when the absolute value of the change amount of the optical power per unit distance is equal to a predetermined value or larger than a predetermined value, the location is specified as an abnormal location. Identification of the abnormal part may be executed by the abnormal part specifying unit 420.

  In step S506, the wavelength-loss characteristics of the optical fiber core line are determined using the information regarding the optical power for each of the plurality of wavelengths and the values of the plurality of wavelengths. At this time, the wavelength versus loss characteristic of the optical fiber core wire may be determined for the abnormal part. Wavelength vs. loss characteristics are, for example, the wavelength of the backscattered light measured with the horizontal axis representing the wavelength, and the vertical axis representing the amount of change in optical power at a specific position of the optical fiber core, and the change in optical power at that wavelength. It can be determined by plotting the quantity. The determination of the wavelength versus loss characteristic may be performed by the characteristic determination unit 432.

In S508, it is determined whether or not the slope of the wavelength versus loss characteristic of the optical fiber core wire is larger than a specified value. For example, it is determined whether or not the macro bending index k _macro obtained using equation (1) is greater than zero. The determination may be performed by the determination unit 434.

If the macro bending index k _macro is greater than 0 (Yes in S508), the degree of bending at the abnormal location of the optical fiber core wire is determined in S510. For example, assuming that the number of turns of the optical fiber core wire in Formula (9) is a specified value, the number of turns of the optical fiber core wire is calculated based on Formula (9) using the wavelength versus loss characteristic and the specified value. The radius of curvature in the case of the specified value is determined. The determination of the curvature radius may be executed by the curvature radius determination unit 436. When the curvature radius is determined, the process is terminated.

If the macro bending index k _macro is not greater than 0 (NO in S508), the degree of axial misalignment at the abnormal portion of the optical fiber core wire is determined in S512. For example, assuming that the ratio of the spot sizes of the two optical fiber core wires connected in Equation (15) is a prescribed value, using the wavelength versus loss characteristic and the prescribed value, based on Equation (15) The amount of axial misalignment of the optical fiber core wire when the ratio is the specified value is determined. The determination of the axis deviation amount may be performed by the axis deviation amount determination unit 438. When the axis deviation amount is determined, the process is terminated. If the macro bending index k _macro is 0, the degree of bending at the abnormal portion of the optical fiber core wire may be determined at S510, and the degree of axial deviation at the abnormal portion of the optical fiber core wire is determined at S512. You may decide.

  The apparatus, method, computer-readable medium, and program for determining at least one of the radius of curvature and the amount of axial deviation using the measurement result from the optical power measurement unit 410 have been described above. In the present embodiment, the optical power measurement unit 410 obtains information regarding optical power for each of a plurality of wavelengths by changing the wavelength of the test light and performing a series of tests in order for each test light. May be. In addition, the optical power measurement unit 410 may acquire information on optical power for each of a plurality of wavelengths by performing a series of tests using test light including a plurality of optical pulses having different wavelengths. In the series of tests, the incidence of the light pulse on the optical fiber core and the measurement of the optical power of the backscattered light are repeatedly performed.

  Here, when performing a series of tests using test light including light pulses of a plurality of wavelengths, changing the wavelength of the test light and performing a series of tests on each test light in turn In comparison, the test time can be shortened. Further, by reducing the test time, the detection accuracy of the abnormal part and the degree of abnormality of the optical fiber core wire is improved.

  For example, when conducting a test of the optical fiber core wire for each of a plurality of test lights having different wavelengths and calculating the wavelength-loss characteristics of the optical fiber core wire, the wavelength of the test light is changed, While the test is being performed, the environment around the optical fiber core line may change, and it may be difficult to improve the detection accuracy. On the other hand, when a series of tests are performed using test light including light pulses of a plurality of wavelengths, the test light including light pulses of a plurality of wavelengths is almost simultaneously or slightly within the repetition period. After a short time, it is sent to the optical fiber core. Therefore, within the repetition period, the environmental conditions around the optical fiber core wire at each time when the test light including a plurality of light pulses is transmitted can be regarded as substantially the same. Thereby, the influence which the change of the environment around an optical fiber core wire has on said detection accuracy can be reduced. In addition, by using test light including light pulses of a plurality of wavelengths, the same purpose can be achieved by a single test instead of the tests that have been performed at each wavelength. Therefore, the test time can be shortened.

  However, when a series of tests are performed using test light including a plurality of optical pulses having different wavelengths, the peak optical power of the optical pulse increases when two or more optical pulses overlap. Therefore, depending on the magnitude of the peak optical power of the optical pulse formed by overlapping two or more optical pulses, at least a part of each part of the abnormality detection device 400 and each part of the optical fiber network may be damaged. In addition, there is a possibility that the influence on the measurement result due to the nonlinear optical effect of the optical fiber cannot be ignored. When the peak optical power when two or more light pulses overlap is greater than about 10 mW, the above problem becomes particularly significant.

  Since the backscattered light is very weak, as the length of the optical fiber increases, an optical pulse having a large peak optical power is used as the test light. Therefore, for example, when the length of the optical fiber to be tested is very long, such as when testing an optical fiber core wire constituting an optical fiber network, if two or more optical pulses overlap, The impact will also increase. Therefore, an optical power measuring unit 410 suitable for testing an optical fiber core wire using test light including a plurality of optical pulses having different wavelengths will be described with reference to FIGS.

  FIG. 6 schematically shows an example of the optical power measurement unit 410. The optical power measurement unit 410 makes the test light 12 incident on the incident end of the optical fiber core wire 10, and is backscattered light 14 from the optical fiber core wire 10, and backscattered from a plurality of positions at different distances from the incident end. The optical power of the light 14 is measured. The optical fiber core wire 10 may be an example of an optical line to be tested. The backscattered light 14 may be an example of reflected light from the optical line with respect to the test light 12.

  In the present embodiment, the optical power measurement unit 410 includes an optical pulse output unit 602, an optical coupling unit 604, an optical demultiplexing unit 606, and a measurement unit 608. The optical pulse output unit 602 includes a light source 622, a light source 624, an optical branching unit 632, an optical branching unit 634, an optical multiplexing unit 640, and an optical pulse control unit 650. The optical pulse controller 650 includes a pulse generator 652, a delay controller 654, and a timing detector 656. The measurement unit 608 includes a light receiving unit 682, a light receiving unit 684, and a signal processing unit 686.

  The optical pulse output unit 602 outputs the test light 12. The optical pulse output unit 602 may alternately output an optical pulse having the first wavelength and an optical pulse having the second wavelength. The first wavelength and the second wavelength may have different values. The optical pulse output unit 602 causes the output optical pulse to enter the incident end of the optical fiber core wire 10 via the optical coupling unit 604, for example. The optical pulse output unit 602 alternately outputs the optical pulse having the first wavelength and the optical pulse having the second wavelength, so that the optical loss measurement accuracy, the abnormal portion of the fiber core wire, and the degree of abnormality Detection accuracy can be improved. Further, damage to each part of the abnormality detection device 400 and each part of the optical fiber network can be prevented.

  The optical coupling unit 604 makes the test light 12 output from the optical pulse output unit 602 enter the incident end of the optical fiber core wire 10. The optical coupling unit 604 takes out the backscattered light 14 from the optical fiber core wire 10 corresponding to the test light 12. The optical coupling unit 604 transmits the extracted backscattered light 14 to the optical demultiplexing unit 606. The backscattered light 14 from the optical fiber core wire 10 includes backscattered light from a plurality of positions having different distances from the incident end. As the optical coupling unit 604, an optical circulator is typically used.

  The optical demultiplexing unit 606 demultiplexes the backscattered light 14 corresponding to each of two optical pulses having different wavelengths included in the test light 12 into light having the first wavelength and light having the second wavelength. To do. The optical demultiplexing unit 606 transmits each of the two demultiplexed lights to the measurement unit 608. The measurement unit 608 measures the optical power of each of the two lights transmitted from the optical demultiplexing unit 606.

  The components of the optical pulse output unit 602 will be described. The light source 622 and the light source 624 output optical pulses. In the present embodiment, the wavelength of the light pulse output from the light source 622 is different from the wavelength of the light pulse output from the light source 624. Further, the peak of the light pulse output from the light source 622 does not match the peak of the light pulse output from the light source 624.

  The light source 622 may output an optical pulse based on the pulse signal generated by the pulse generator 652. The light source 624 may output an optical pulse based on the pulse signal φ24 delayed by the delay control unit 654. The light pulse output from the light source 622 may be an example of a first light pulse. The light pulse output from the light source 624 may be an example of a second light pulse.

  The light branching unit 632 branches the light output from the light source 622. The optical branching unit 632 transmits one of the branched lights to the optical multiplexing unit 640 and transmits the other of the branched light to the optical pulse control unit 650. The light branching unit 634 branches the light output from the light source 624. The optical branching unit 634 transmits one of the branched lights to the optical multiplexing unit 640 and transmits the other of the branched lights to the optical pulse control unit 650.

  The optical multiplexing unit 640 multiplexes the optical pulse output from the light source 622 and the optical pulse output from the light source 624. In the present embodiment, the optical multiplexing unit 640 generates the test light 12 by multiplexing the light transmitted from the optical branching unit 632 and the light transmitted from the optical branching unit 634.

  The optical pulse controller 650 controls the timing at which the light source 622 outputs an optical pulse and the timing at which the light source 624 outputs an optical pulse. The light pulse controller 650 controls the timing of the light source 622 so that the timing at which the light source 622 outputs the light pulse does not coincide with the timing at which the light source 624 outputs the light pulse.

  Explaining each part of the optical pulse controller 650, the pulse generator 652 generates a pulse signal. In the present embodiment, the pulse generator 652 generates a pulse signal φ20, a pulse signal φ22, and a pulse signal φ46. The pulse signal φ20, the pulse signal φ22, and the pulse signal φ46 are output after being synchronized, and transmitted to the delay control unit 654, the light source 622, and the signal processing unit 686, respectively.

  In the present embodiment, the pulse signal φ20 is used to generate a pulse signal φ24 that defines the generation timing of an optical pulse in the light source 624. The pulse signal φ22 defines the generation timing of the optical pulse in the light source 622. The pulse signal φ46 defines the sampling timing of A / D conversion in the signal processing unit 686.

  The delay control unit 654 delays the pulse signal φ20 generated by the pulse generation unit 652 to generate the pulse signal φ24. The delay control unit 654 transmits the generated pulse signal φ24 to the light source 624. The delay control unit 654 may generate the pulse signal φ24 so that the timing at which the light source 622 outputs an optical pulse does not match the timing at which the light source 624 outputs an optical pulse.

  The delay control unit 654 generates a pulse signal based on the output timing of the light pulse output from the light source 622 and the light pulse output from the light source 624 detected by the timing detection unit 656 so that the two light pulses do not overlap. The time for delaying φ24 may be adjusted. For example, in the present embodiment, the delay control unit 654 determines the delay amount of the pulse signal φ24 with respect to the pulse signal φ22 based on the timing signal φ26 transmitted from the timing detection unit 656.

  The timing detection unit 656 detects the output timing of the light pulse output from the light source 622 and the light pulse output from the light source 624. The timing detection unit 656 receives part of the light output from the light source 622 from the light branching unit 632. The timing detection unit 656 receives a part of the light output from the light source 624 from the light branching unit 634. The timing detection unit 656 detects the output timing of the light pulse output from the light source 622 and the light pulse output from the light source 622 based on the light received from the light branching unit 632 and the light branching unit 634.

  The timing detection unit 656 may detect the output timing of the two optical pulses by detecting the timing itself at which each of the two optical pulses is output. The timing detection unit 656 may detect the output timing of the two optical pulses by detecting the timing difference between the peaks of the two optical pulses. The timing detection unit 656 may detect the output timing of the two light pulses by determining whether or not the peaks of the two light pulses are the same.

  The timing detection unit 656 generates a timing signal φ26 based on the output timings of the two optical pulses. The timing signal φ26 may include information regarding the timing at which the light source 622 outputs an optical pulse and the timing at which the light source 624 outputs an optical pulse. The timing detection unit 656 transmits the generated timing signal φ26 to the delay control unit 654.

  In the present embodiment, the case where the pulse generation unit 652 generates the pulse signal φ20 and the pulse signal φ22 and the delay control unit 654 delays the pulse signal φ20 to generate the pulse signal φ24 has been described. However, the method for generating the pulse signal φ24 is not limited to the above embodiment. The pulse generation unit 652 may generate the pulse signal φ22 and transmit it to the light source 622 and the delay control unit 654, and the delay control unit 654 may delay the pulse signal φ22 to generate the pulse signal φ24.

  Explaining each part of the measurement unit 608, the light receiving unit 682 and the light receiving unit 684 convert the received optical signal into an electrical signal. The light receiving unit 682 converts the light having the first wavelength demultiplexed by the light demultiplexing unit 606 into a light receiving signal φ42. The light receiving unit 682 transmits a light receiving signal φ42 to the signal processing unit 686. The light receiving unit 684 converts the light having the second wavelength demultiplexed by the light demultiplexing unit 606 into a light receiving signal φ44. The light receiving unit 684 transmits a light reception signal φ44 to the signal processing unit 686.

  The signal processing unit 686 samples the light reception signal φ42 and the light reception signal φ44 according to the pulse signal φ46, and A / D converts the light reception signal φ42 and the light reception signal φ44. The signal processing unit 686 measures the optical power of the backscattered light 14 based on the A / D converted amplitude data. The signal processing unit 686 measures the position of the backscattered light 14 from which position in the optical fiber core wire 10 based on the time from when the pulsed light is output from the light source until it returns to the incident end. Thereby, the loss distribution of the optical fiber core wire 10 can be acquired.

  An optical power measurement process in the optical power measurement unit 410 will be schematically described. In the present embodiment, the optical power measurement unit 410 alternately outputs an optical pulse having a first wavelength and an optical pulse having a second wavelength, to the incident end of the optical fiber core wire 10 to be tested, Test light 12 is incident. When the test light 12 enters the optical fiber core wire 10, backscattered light from a plurality of positions with different distances from the incident end returns to the incident end. The optical power measurement unit 410 extracts the backscattered light 14 from the optical fiber core wire 10 and demultiplexes the backscattered light 14 into light having a first wavelength and light having a second wavelength. The optical power measurement unit 410 measures the optical power of each of the light having the first wavelength and the light having the second wavelength. Thereby, the loss distribution of the optical fiber core wire 10 can be acquired.

  The optical power measurement unit 410 may make the test light 12 enter the optical fiber core wire a plurality of times with an appropriate time interval. Thereby, the process of alternately entering the optical pulse having the first wavelength and the optical pulse having the second wavelength into the optical fiber core wire 10 is repeated. The optical power measurement unit 410 may obtain the loss distribution of the optical fiber core wire 10 by averaging the measurement results obtained by multiple incidences. Thereby, the noise contained in said loss distribution can be reduced.

  In the present embodiment, the case where the optical power measuring unit 410 tests the optical fiber core wire 10 using the test light 12 including two optical pulses having different wavelengths has been described. However, the optical power measurement unit 410 is not limited to this. The optical power measurement unit 410 may test the optical fiber core wire 10 using the test light 12 including two or more optical pulses having different wavelengths. In this case, the optical pulse output unit 602 may output two or more optical pulses having different wavelengths so that the two or more optical pulses having different wavelengths are sequentially repeated. In addition, the optical power measurement unit 410 and the optical pulse output unit 602 may be used for applications other than OTDR.

  FIG. 7 schematically shows an example of the test light 12 of the optical power measurement unit 410. An example of the relationship between the test light 12 and the pulse signal φ22 and the pulse signal φ24 will be described with reference to FIG. The test light 12 includes an optical pulse 712 having a first wavelength and an optical pulse 714 having a second wavelength. The pulse signal φ22 defines the output timing of the optical pulse 712. The pulse signal φ24 defines the output timing of the optical pulse 714.

The pulse signal φ22 includes one or more pulses having a period T ₁ and a pulse width τ ₁ . The pulses may, for example, occurs at time _{t 1-1} and the time _{t 1-2.} Pulse signal φ24 may include one or more pulses having a period T ₂ and the pulse width tau _2. The pulse is generated, for example, at time t _2-1 and time t _2-2 . The period T ₁ and the period T ₂ are preferably the same. The pulse width τ ₁ and the pulse width τ ₂ are preferably the same.

The pulse signal φ24 is delayed with respect to the pulse signal φ22 by a time corresponding to t _2-1 −t _1-1 , and is adjusted so that the peak of the pulse signal φ22 and the peak of the pulse signal φ24 do not coincide with each other. ing. As apparent from FIG. 7, when the test light 12 is incident on the optical fiber core wire 10, the optical fiber core wire 10 alternately has an optical pulse 712 having a first wavelength and an optical pulse 714 having a second wavelength. Incident.

  FIG. 8 schematically shows an example of the timing detection unit 656. The timing detection unit 656 generates a timing signal φ26 including information indicating whether or not the peaks of a plurality of optical pulses are coincident. The timing detection unit 656 includes an optical multiplexing unit 810, a light receiving unit 820, and a peak detection unit 830.

  The optical multiplexing unit 810 receives part of the light output from the light source 622 from the optical branching unit 632. The optical multiplexing unit 810 receives a part of the light output from the light source 624 from the optical branching unit 634. The optical multiplexing unit 810 combines the light transmitted from the optical branching unit 632 and the light transmitted from the optical branching unit 634. The optical multiplexing unit 810 transmits the combined light to the light receiving unit 820.

  The light receiving unit 820 converts the received optical signal into an electrical signal. The light receiving unit 820 converts the light combined by the light combining unit 810 into a light reception signal φ82. The light receiving unit 820 transmits a light receiving signal φ82 to the peak detecting unit 830.

  The peak detector 830 detects the peak component of the light reception signal φ82. The peak detector 830 generates a timing signal φ26 including information indicating the magnitude of the detected peak component. The peak detection unit 830 transmits the timing signal φ26 to the delay control unit 654.

  When the magnitude of the peak detected by the peak detection unit 830 is smaller than a predetermined value, the delay control unit 654 outputs the light pulse from the light source 622 and the light source 624 outputs the light pulse. It may be determined that the timing does not match, and the delay amount or the necessity of changing the delay amount may be determined. When the magnitude of the peak detected by the peak detection unit 830 is larger than a predetermined value, the delay control unit 654 outputs the light pulse from the light source 622 and the light source 624 outputs the light pulse. It may be determined that the timing matches, and the delay amount or the necessity of changing the delay amount may be determined.

  According to another embodiment, for example, when the peak detected by the peak detector 830 is smaller than a predetermined value, the peak detector 830 causes the light source 622 to output an optical pulse. A timing signal φ26 including information indicating that the timing and the timing at which the light source 624 outputs an optical pulse does not match is generated. For example, when the magnitude of the peak detected by the peak detector 830 is larger than a predetermined value, the timing signal φ26 including information indicating that the timings of both coincide is generated. In this case, the delay control unit 654 may determine the delay amount or whether or not the delay amount needs to be changed based on the timing signal φ26.

  FIG. 9 schematically shows an example of the timing detection unit 956. The timing detection unit 956 generates a timing signal φ26 including information indicating the correlation between a plurality of optical pulses. The timing detection unit 956 includes a light receiving unit 922, a light receiving unit 924, and a correlation processing unit 930.

  The light receiving unit 922 and the light receiving unit 924 convert the received optical signal into an electrical signal. The light receiving unit 922 receives part of the light output from the light source 622 from the light branching unit 632. The light receiving unit 922 converts the light transmitted from the light branching unit 632 into a light receiving signal φ92. The light receiving unit 922 transmits the light reception signal φ92 to the correlation processing unit 930. The light receiving unit 924 receives part of the light output from the light source 624 from the light branching unit 634. The light receiving unit 924 converts the light transmitted from the light branching unit 634 into a light receiving signal φ94. The light receiving unit 924 transmits the light reception signal φ94 to the correlation processing unit 930.

  Correlation processing unit 930 executes a correlation processing calculation between light reception signal φ92 and light reception signal φ94. The correlation processing unit 930 generates the timing signal φ26 based on the calculation result. The delay control unit 654 may determine the delay amount or necessity of changing the delay amount based on the timing signal φ26.

  FIG. 10 schematically shows an example of the timing detection unit 1056. The timing detection unit 1056 generates a timing signal φ26 including information indicating whether or not the peaks of a plurality of optical pulses are coincident. The timing detection unit 1056 includes a light receiving unit 1022, a light receiving unit 1024, an addition processing unit 1032, and a peak detection unit 1034.

  The light receiving unit 1022 and the light receiving unit 1024 convert the received optical signal into an electrical signal. The light receiving unit 1022 receives part of the light output from the light source 622 from the light branching unit 632. The light receiving unit 1022 converts the light transmitted from the light branching unit 632 into a light receiving signal φ103. The light receiving unit 1022 transmits the light reception signal φ103 to the addition processing unit 1032. The light receiving unit 1024 receives part of the light output from the light source 624 from the light branching unit 634. The light receiving unit 1024 converts the light transmitted from the light branching unit 634 into a light receiving signal φ104. The light receiving unit 1024 transmits the light reception signal φ104 to the addition processing unit 1032.

  The addition processing unit 1032 performs an addition processing operation between the light reception signal φ103 and the light reception signal φ104. Based on the calculation result, the addition processing unit 1032 generates an addition signal φ 106 corresponding to a light reception signal of light obtained by combining the light transmitted from the optical branching unit 632 and the light transmitted from the optical branching unit 634. The addition processing unit 1032 transmits the addition signal φ106 to the peak detection unit 1034.

  The peak detection unit 1034 detects a signal corresponding to the peak component of the light obtained by combining the light transmitted from the optical branching unit 632 and the light transmitted from the optical branching unit 634 based on the addition signal φ106. The peak detector 1034 generates a timing signal φ26 including information indicating the magnitude of the detected signal. The peak detection unit 1034 transmits the timing signal φ26 to the delay control unit 654. The delay control unit 654 may determine whether or not the delay amount or the delay amount needs to be changed in the same manner as when the timing signal φ26 is received from the timing detection unit 656.

  According to another embodiment, for example, when the magnitude of the peak detected by the peak detection unit 1034 is smaller than a predetermined value, the peak detection unit 1034 causes the light source 622 to output an optical pulse. A timing signal φ26 including information indicating that the timing and the timing at which the light source 624 outputs an optical pulse does not match is generated. For example, when the magnitude of the peak detected by the peak detection unit 1034 is larger than a predetermined value, the peak detection unit 1034 includes a timing signal φ26 including information indicating that the timings of both coincide with each other. Is generated. In this case, the delay control unit 654 may determine the delay amount or whether or not the delay amount needs to be changed based on the timing signal φ26.

  FIG. 11 schematically illustrates an example of the optical power measurement unit 1110. An optical pulse output unit 1102, an optical coupling unit 604, an optical demultiplexing unit 606, and a measurement unit 608 are provided. The optical power measurement unit 1110 is different from the optical power measurement unit 410 in that an optical pulse output unit 1102 is provided instead of the optical pulse output unit 602. Other configurations may be the same as those of the optical power measurement unit 410.

  The optical pulse output unit 1102 includes a wavelength variable light source 1122 instead of the light source 622, the light source 624, and the optical multiplexing unit 640, a point including an optical pulse control unit 1150 instead of the optical pulse control unit 650, and an optical branching unit. The optical pulse output unit 602 is different from the optical pulse output unit 602 in that it does not include 632 and the optical branching unit 634. Other configurations may be the same as those of the optical pulse output unit 602.

  The variable wavelength light source 1122 can generate light having different wavelengths. The wavelength tunable light source 1122 includes a modulation terminal to which a modulation signal φ112 indicating timing for generating light is input, and a wavelength variable terminal to which a wavelength control signal φ114 for controlling the wavelength of light to be generated is applied. By controlling the modulation signal φ112 and the wavelength control signal φ114, the optical pulse output unit 1102 can output the test light 12 similar to the optical pulse output unit 602. Modulation signal φ112 is generated by pulse generator 652. The wavelength control signal φ114 is generated by the wavelength control unit 1114. The wavelength control unit 1114 operates according to the pulse signal φ110 generated by the pulse generation unit 652. The pulse signal φ110 and the modulation signal φ112 may be synchronized.

  FIG. 12 schematically shows an example of the test light 12 of the optical power measurement unit 1110. An example of the relationship between the test light 12, the modulation signal φ112, and the wavelength control signal φ114 will be described with reference to FIG. The modulation signal φ112 defines the output timing of the optical pulse 712 and the optical pulse 714. The wavelength control signal φ114 defines the wavelengths of the optical pulse 712 and the optical pulse 714.

Modulated signal φ112 includes 1 and more pulses having a period T ₁ and a pulse width tau _1, and one or more pulses having a period T ₂ and the pulse width tau _2. A pulse having a period T ₁ and a pulse width τ ₁ occurs, for example, at time t _1-1 and time t _1-2 . A pulse having a period T ₂ and a pulse width τ ₂ is generated at time t _2-1 and time t _2-2 , for example. In the modulation signal Fai112, a pulse having a period T ₁ and a pulse width tau _1, and the pulse having a period T ₂ and the pulse width tau _2, alternately generated. The period T ₁ and the period T ₂ are preferably the same. The pulse width τ ₁ and the pulse width τ ₂ are preferably the same.

Wavelength control signal φ114 includes one or more pulses having a period _{T 3} and the pulse width tau _3. The pulse having the period T ₃ and the pulse width τ ₃ is the pulse having the period T ₂ and the pulse width τ ₂ of the modulation signal φ 112 after the pulse having the period T ₁ and the pulse width τ ₁ of the modulation signal φ 112 has fallen. Get up before you get up. The pulse having the period T ₃ and the pulse width τ ₃ is a pulse having the period T ₁ and the pulse width τ ₁ of the modulation signal φ 112 after the pulse having the period T ₂ and the pulse width τ ₂ of the modulation signal φ 112 falls. It falls before the next pulse rises. A pulse having a period T ₃ and a pulse width τ ₃ occurs, for example, at time t _3-1 and time t _3-2 . The period T ₁ , the period T _2, and the period T ₃ are preferably the same.

  By the modulation signal φ112 and the wavelength control signal φ114, the wavelength tunable light source 1122 includes the optical pulse 712 having the first wavelength and the optical pulse 714 having the second wavelength so that the peaks of both do not match. Test light 12 can be generated. The above embodiment is an example of the modulation signal φ112 and the wavelength control signal φ114, and the modulation signal φ112 and the wavelength control signal φ114 are not limited to the above embodiment.

  The execution order of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior”. It should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. is not.

From the above description, it is clear that the following matters are described in the present specification.
(Item 1)
For each of the plurality of wavelengths obtained by measuring the optical power of the backscattered light from a plurality of positions at different distances from the incident end of the light incident from the incident end of the optical fiber core wire, for a plurality of wavelengths. Using the information on the optical power and the values of the plurality of wavelengths, a characteristic determining unit that determines a wavelength-loss characteristic of the optical fiber core wire,
Assuming that the number of turns of the optical fiber core wire is a first specified value, the number of turns of the optical fiber core wire is the first specified value using the wavelength versus loss characteristic and the first specified value. A curvature radius determining unit for determining a curvature radius of the first portion of the optical fiber core wire in the case of
An apparatus comprising:
(Item 2)
For each of the plurality of wavelengths obtained by measuring the optical power of the backscattered light from a plurality of positions at different distances from the incident end of the light incident from the incident end of the optical fiber core wire, for a plurality of wavelengths. Using the information on the optical power and the values of the plurality of wavelengths, a characteristic determining unit that determines a wavelength-loss characteristic of the optical fiber core wire,
Assuming that the ratio of the spot sizes of the two optical fiber cores to be connected is a second specified value, the ratio is the second specified value by using the wavelength-to-loss characteristic and the second specified value. An axial deviation amount determining unit for determining an axial deviation amount of the first portion of the optical fiber core wire when the specified value is
An apparatus comprising:
(Item 3)
For each of the plurality of wavelengths obtained by measuring the optical power of the backscattered light from a plurality of positions at different distances from the incident end of the light incident from the incident end of the optical fiber core wire for a plurality of wavelengths. Determining the wavelength-loss characteristics of the optical fiber core wire using the information on the optical power and the values of the plurality of wavelengths,
Assuming that the number of turns of the optical fiber is a first specified value, the number of turns of the optical fiber is the first specified value using the wavelength versus loss characteristic and the first specified value. Determining a radius of curvature of the first location of the optical fiber core in the case;
Having a method.
(Item 4)
For each of the plurality of wavelengths obtained by measuring the optical power of the backscattered light from a plurality of positions at different distances from the incident end of the light incident from the incident end of the optical fiber core wire, for a plurality of wavelengths. Using the information about the optical power and the values of the plurality of wavelengths to determine the wavelength-loss characteristics of the optical fiber core;
Assuming that the ratio of the spot sizes of the two optical fiber cores to be connected is a second specified value, the ratio is the second specified value by using the wavelength-to-loss characteristic and the second specified value. Determining the amount of axial misalignment of the first portion of the optical fiber core wire when the specified value is
Having a method.
(Item 5)
A computer-readable medium for storing a program,
The program is a computer-readable medium that causes a computer to function as the apparatus according to item 1 or item 2.
(Item 5)
A program for causing a computer to function as the device according to item 1 or item 2.
[Appendix 1]
An optical pulse output unit that alternately outputs a first optical pulse having a first wavelength and a second optical pulse having a second wavelength, and is incident on an incident end of the optical fiber core;
Backscattered light from the optical fiber core line corresponding to each of the first light pulse and the second light pulse, and backscattered light from a plurality of positions having different distances from the incident end, An optical demultiplexing unit that demultiplexes light having a first wavelength and light having the second wavelength;
A measuring unit for measuring the optical power of each of the light having the first wavelength and the light having the second wavelength;
A measuring device.
[Appendix 2]
The optical pulse output unit is
A first light source that outputs the first light pulse;
A second light source for outputting the second light pulse;
An optical pulse controller that controls the timing at which the first light source outputs the first optical pulse and the timing at which the second light source outputs the second optical pulse;
An optical multiplexing unit for multiplexing the first optical pulse and the second optical pulse;
Having
The measuring apparatus according to appendix 1.
[Appendix 3]
The optical pulse controller is
A pulse generator for generating a pulse signal;
A delay controller for delaying the pulse signal generated by the pulse generator;
With
The first light source outputs the first light pulse based on the pulse signal generated by the pulse generator,
The second light source outputs the second optical pulse based on the pulse signal delayed by the delay control unit.
The measuring apparatus according to attachment 2.
[Appendix 4]
A timing detector for detecting the output timing of the first optical pulse and the second optical pulse;
The delay control unit prevents the first optical pulse and the second optical pulse from overlapping based on the output timing of the first optical pulse and the second optical pulse detected by the timing detection unit. Adjusting the time for delaying the pulse signal,
The measuring apparatus according to attachment 3.
[Appendix 5]
The optical pulse output unit has a wavelength variable light source,
The measuring apparatus according to appendix 1.
[Appendix 6]
An optical pulse output stage that alternately outputs a first optical pulse having a first wavelength and a second optical pulse having a second wavelength and is incident on an incident end of an optical fiber core wire to be tested;
Backscattered light from the optical fiber core line corresponding to each of the first light pulse and the second light pulse, and backscattered light from a plurality of positions having different distances from the incident end, An optical demultiplexing stage for demultiplexing light having a first wavelength and light having the second wavelength;
A measuring step of measuring the optical power of each of the light having the first wavelength and the light having the second wavelength;
A measuring method.
[Appendix 7]
The measuring apparatus according to any one of appendices 1 to 5,
Information relating to the optical power measured by the measuring device, the information relating to the optical power for each of the backscattered light corresponding to each of the first optical pulse and the second optical pulse, and A characteristic determining unit that determines a wavelength-loss characteristic of the optical fiber core wire by using the wavelength values of the first optical pulse and the second optical pulse;
Assuming that the number of turns of the optical fiber core wire is the first specified value, the number of turns of the optical fiber core wire is the first specified value using the wavelength versus loss characteristic and the first specified value. A curvature radius determining unit for determining a curvature radius of the first portion of the optical fiber core wire in the case of
An apparatus comprising:
[Appendix 8]
The measuring apparatus according to any one of appendices 1 to 5,
Information relating to the optical power measured by the measuring device, the information relating to the optical power for each of the backscattered light corresponding to each of the first optical pulse and the second optical pulse, and A characteristic determining unit that determines a wavelength-loss characteristic of the optical fiber core wire by using the wavelength values of the first optical pulse and the second optical pulse;
Assuming that the ratio of the spot sizes of the two optical fiber core wires to be connected is the second specified value, the ratio is the second specified value using the wavelength-to-loss characteristic and the second specified value. An axial deviation amount determining unit for determining an axial deviation amount of the first portion of the optical fiber core wire when the specified value is
An apparatus comprising:

  10 optical fiber core wire, 12 test light, 14 back scattered light, 101 graph, 102 graph, 201 graph, 202 graph, 203 graph, 204 graph, 205 graph, 206 graph, 207 graph, 208 graph, 209 graph, 210 graph, 211 graph, 301 graph, 302 graph, 303 graph, 304 graph, 305 graph, 400 anomaly detection device, 410 optical power measurement unit, 420 anomaly location specifying unit, 430 anomaly amount determining unit, 432 characteristic determining unit, 434 determining unit, 436 Curvature radius determining unit, 438 Axis deviation determining unit, 440 Optical fiber core line database, 602 Optical pulse output unit, 604 Optical coupling unit, 606 Optical demultiplexing unit, 608 Measuring unit, 622 Light source, 624 Light source, 632 Optical branching unit , 634 Light branch , 640 optical multiplexing unit, 650 optical pulse control unit, 652 pulse generation unit, 654 delay control unit, 656 timing detection unit, 682 light receiving unit, 684 light receiving unit, 686 signal processing unit, 712 optical pulse, 714 optical pulse, 810 optical multiplexing Wave unit, 820 light receiving unit, 830 peak detecting unit, 922 light receiving unit, 924 light receiving unit, 930 correlation processing unit, 956 timing detection unit, 1022 light receiving unit, 1024 light receiving unit, 1032 addition processing unit, 1034 peak detection unit, 1056 timing Detection unit, 1102 Optical pulse output unit, 1110 Optical power measurement unit, 1114 Wavelength control unit, 1122 Wavelength variable light source, 1150 Optical pulse control unit

Claims (12)

An optical pulse output unit that alternately outputs a first optical pulse having a first wavelength and a second optical pulse having a second wavelength, and is incident on an incident end of the optical fiber core;
Backscattered light from the optical fiber core line corresponding to each of the first light pulse and the second light pulse, and backscattered light from a plurality of positions with different distances from the incident end, An optical demultiplexing unit that demultiplexes light having a first wavelength and light having the second wavelength;
A measuring unit for measuring the optical power of each of the light having the first wavelength and the light having the second wavelength;
Bei to give a,
The light pulse output unit includes a timing at which a first light source that outputs the first light pulse outputs the first light pulse, and a second light source that outputs the second light pulse is the first light source. An optical pulse controller that controls the timing of outputting two optical pulses,
The optical pulse controller is
A pulse generator for generating a pulse signal;
A delay controller for delaying the pulse signal generated by the pulse generator;
A timing detector for detecting the output timing of the first optical pulse and the second optical pulse;
Have
The timing detection unit generates a timing signal indicating whether or not the peaks of the first optical pulse and the second optical pulse match,
The delay control unit adjusts a time for delaying the pulse signal based on the timing signal so that the first optical pulse and the second optical pulse do not overlap,
The first light source outputs the first optical pulse based on the pulse signal generated by the pulse generator,
The second light source outputs the second optical pulse based on the pulse signal delayed by the delay control unit.
measuring device.   The timing detector
  An optical multiplexing unit for timing detection for multiplexing a part of the first optical pulse and a part of the second optical pulse;
  A peak detection unit that detects a peak component of the light combined by the timing detection optical multiplexing unit and generates the timing signal including information indicating a size of the peak component;
  Comprising
  The measuring apparatus according to claim 1.   The timing detector
  A first light receiving unit that receives a part of the first light pulse and converts it into a first electric signal;
  A second light-receiving unit that receives a part of the second light pulse and converts it into a second electric signal;
  An addition processing unit for adding the first electric signal and the second electric signal;
  Based on a calculation result of the addition processing unit, a signal corresponding to a peak component of light obtained by combining a part of the first optical pulse and a part of the second optical pulse is detected, and the peak component is detected. A peak detector for generating the timing signal including information indicating the magnitude of
  Comprising
  The measuring apparatus according to claim 1.   An optical pulse output unit that alternately outputs a first optical pulse having a first wavelength and a second optical pulse having a second wavelength, and is incident on an incident end of the optical fiber core;
  Backscattered light from the optical fiber core line corresponding to each of the first light pulse and the second light pulse, and backscattered light from a plurality of positions with different distances from the incident end, An optical demultiplexing unit that demultiplexes light having a first wavelength and light having the second wavelength;
  A measuring unit for measuring the optical power of each of the light having the first wavelength and the light having the second wavelength;
  With
  The light pulse output unit includes a timing at which a first light source that outputs the first light pulse outputs the first light pulse, and a second light source that outputs the second light pulse is the first light source. An optical pulse controller that controls the timing of outputting two optical pulses,
  The optical pulse controller is
  A pulse generator for generating a pulse signal;
  A delay controller for delaying the pulse signal generated by the pulse generator;
A timing detector for detecting the output timing of the first optical pulse and the second optical pulse;
  Have
  The timing detection unit generates a timing signal including information indicating a correlation between the first optical pulse and the second optical pulse;
  The delay control unit adjusts a time for delaying the pulse signal based on the timing signal so that the first optical pulse and the second optical pulse do not overlap,
The first light source outputs the first optical pulse based on the pulse signal generated by the pulse generator,
The second light source outputs the second optical pulse based on the pulse signal delayed by the delay control unit.
measuring device. The optical pulse output unit is
A first light source that outputs the first light pulse;
A second light source that outputs the second light pulse ;
An optical multiplexing unit for multiplexing the first optical pulse and the second optical pulse;
Further having
The measuring apparatus as described in any one of Claim 1- Claim 4 . The optical pulse output unit has a wavelength variable light source,
The measuring device according to any one of claims 1 to 5 . An optical pulse output stage that alternately outputs a first optical pulse having a first wavelength and a second optical pulse having a second wavelength and is incident on an incident end of an optical fiber core wire to be tested;
Backscattered light from the optical fiber core line corresponding to each of the first light pulse and the second light pulse, and backscattered light from a plurality of positions with different distances from the incident end, An optical demultiplexing stage for demultiplexing into light having a first wavelength and light having the second wavelength;
Have a measurement step of measuring the respective optical power of light with a light and the second wavelength having the first wavelength,
In the optical pulse output step, a timing at which the first light source that outputs the first optical pulse outputs the first optical pulse, and a second light source that outputs the second optical pulse is the first light source. An optical pulse control stage for controlling the timing of outputting two optical pulses,
The optical pulse control step includes
A pulse generation stage for generating a pulse signal;
A delay control step of delaying the pulse signal generated in the pulse generation step;
A timing detection step of detecting an output timing of the first optical pulse and the second optical pulse;
Have
The timing detection step includes generating a timing signal indicating whether or not the peaks of the first optical pulse and the second optical pulse coincide;
The delay control step has a step of adjusting a time for delaying the pulse signal based on the timing signal so that the first optical pulse and the second optical pulse do not overlap each other,
The optical pulse output step includes:
The first light source outputting the first optical pulse based on the pulse signal generated in the pulse generation step;
The second light source outputting the second optical pulse based on the pulse signal delayed in the delay control step;
Having
Measuring method.   The timing detection step includes
  An optical multiplexing stage for timing detection for combining a part of the first optical pulse and a part of the second optical pulse;
  A peak detection stage for detecting a peak component of light combined in the timing detection optical multiplexing stage, and generating the timing signal including information indicating the magnitude of the peak component;
  Having
  The measuring method according to claim 7.   The timing detection step includes
  Receiving a part of the first light pulse and converting it into a first electrical signal;
  Receiving a portion of the second light pulse and converting it to a second electrical signal;
  An addition processing step of adding the first electric signal and the second electric signal;
  Based on a calculation result in the addition processing step, a signal corresponding to a peak component of light obtained by combining a part of the first optical pulse and a part of the second optical pulse is detected, and the peak component is detected. A peak detection step for generating the timing signal including information indicating a magnitude of
  Having
  The measuring method according to claim 7.   An optical pulse output stage for alternately outputting a first optical pulse having a first wavelength and a second optical pulse having a second wavelength and entering the incident end of the optical fiber core;
  Backscattered light from the optical fiber core line corresponding to each of the first light pulse and the second light pulse, and backscattered light from a plurality of positions with different distances from the incident end, An optical demultiplexing stage for demultiplexing into light having a first wavelength and light having the second wavelength;
  A measurement step of measuring the optical power of each of the light having the first wavelength and the light having the second wavelength;
  Have
  In the optical pulse output step, a timing at which the first light source that outputs the first optical pulse outputs the first optical pulse, and a second light source that outputs the second optical pulse is the first light source. An optical pulse control stage for controlling the timing of outputting two optical pulses,
  The optical pulse control step includes
  A pulse generation stage for generating a pulse signal;
  A delay control step of delaying the pulse signal generated in the pulse generation step;
A timing detection step of detecting an output timing of the first optical pulse and the second optical pulse;
  Have
  The timing detection step includes generating a timing signal including information indicating a correlation between the first optical pulse and the second optical pulse;
  The delay control step has a step of adjusting a time for delaying the pulse signal based on the timing signal so that the first optical pulse and the second optical pulse do not overlap each other,
The optical pulse output step includes:
The first light source outputting the first optical pulse based on the pulse signal generated in the pulse generation step;
The second light source outputs the second optical pulse based on the pulse signal delayed in the delay control step;
Having
Measuring method. A measuring device according to any one of claims 1 to 6 ,
Information relating to the optical power measured by the measuring device, the information relating to the optical power for each of the backscattered light corresponding to each of the first optical pulse and the second optical pulse, and A characteristic determining unit that determines a wavelength-loss characteristic of the optical fiber core wire using a wavelength value of the first optical pulse and the second optical pulse;
Assuming that the number of turns of the optical fiber core wire is the first specified value, the number of turns of the optical fiber core wire is the first specified value using the wavelength versus loss characteristic and the first specified value. A curvature radius determining unit for determining a curvature radius of the first portion of the optical fiber core wire in the case of
An apparatus comprising: A measuring device according to any one of claims 1 to 6 ,
Information relating to the optical power measured by the measuring device, the information relating to the optical power for each of the backscattered light corresponding to each of the first optical pulse and the second optical pulse, and A characteristic determining unit that determines a wavelength-loss characteristic of the optical fiber core wire using a wavelength value of the first optical pulse and the second optical pulse;
Assuming that the ratio of the spot sizes of the two optical fiber cores to be connected is a second specified value, the ratio is the second specified value using the wavelength-to-loss characteristic and the second specified value. An axial deviation amount determining unit for determining an axial deviation amount of the first portion of the optical fiber core wire in the case of the specified value of
An apparatus comprising: