JP4781906B2 - Optical fiber core contrast method and optical fiber core contrast device using the same - Google Patents

Description

  The present invention relates to an optical fiber core wire comparison method and an optical fiber core wire contrast device using the same, and particularly when applied to conducting an optical continuity test in the construction and operation of an optical line in an optical transmission system. It is valid.

  When conducting the optical continuity test in the construction and operation of an optical line in an optical transmission system, when finding the target optical fiber core from among a plurality of optical fiber cores, the target optical fiber It is important that the core wire can be easily identified at the work site. For this reason, for example, light is propagated to the target optical fiber core, the arbitrary optical fiber core wire is bent, and the light propagating in the target optical fiber core wire is transmitted to the arbitrary optical fiber. An optical fiber core control for determining whether or not any of the optical fiber cores is a target optical fiber core wire by detecting whether the bent portion of the core wire leaks or not A device is known (see, for example, Non-Patent Document 1 below).

“Optical Fiber Contrast Technology“ Optical Fiber ID Tester R ””, NTT Innovative Technology Site Communication Network (Design / Operation Support) N610, [online], May 31, 2005, Nippon Telegraph and Telephone Corporation, Intellectual Property Center, [Search April 12, 2006], Internet <URL: http://www.ntt-tec.jp/technology/N610.html> Hiroshi Kuchiami and Kuniharu Himeno, “Latest Trends in Access Fiber Optic Cables and Optical Fibers”, Oplus E, New Technology Communications, Inc., June 25, 2004, Vol. 26, No. 7, p. 799-805

  However, in an optical fiber core wire that has recently been attracting attention and has greatly improved bending loss characteristics (for example, see Non-Patent Document 2 above), light hardly leaks even when bent, as described above. A conventional optical fiber core contrast device could not be used.

  For this reason, the present invention uses an optical fiber core contrast method and an optical fiber core contrast method capable of easily performing a core wire contrast operation even for an optical fiber core wire having greatly improved bending loss characteristics. An object of the present invention is to provide an optical fiber core contrast device.

In order to solve the above-described problems, an optical fiber core wire comparison method according to the present invention is an optical fiber core wire that identifies a target optical fiber core wire from a plurality of optical fiber core wires that do not leak light even when bent. In the control method, an arbitrary optical fiber core is bent at a bending radius of 10 mm or more, and a wavelength of 0.5 to 1.0 mm is exceeded upstream of the bent portion of the optical fiber core in the light propagation direction. By irradiating a sound wave to form a diffraction grating inside the optical fiber core, light propagating in the target optical fiber core can be transmitted from the bent portion of any optical fiber core. detects whether leakage, any of the optical fiber, characterized in that determining whether a said optical fiber of interest.

On the other hand, an optical fiber core contrast device according to the present invention for solving the above-described problems is an optical fiber that identifies a target optical fiber core from a plurality of optical fiber cores that do not leak light even when bent. A core contrast device, a holding means for holding an arbitrary optical fiber core, and a wavelength of 0.5 to 1.0 mm provided on the optical fiber core wire provided in the holding means and held by the holding means wherein the ultrasonic irradiation means for forming a diffraction grating on the inside of the optical fiber is irradiated with ultrasonic waves so as to be positioned in the light propagation direction downstream of the optical fiber than the ultrasonic irradiation means A light receiving means provided in the holding means for detecting light leaking from the optical fiber core wire held by the holding means; and the optical fiber core held by the holding means based on information from the light receiving means. The line is intended And a determining unit that determines whether a fiber core, the holding means, the optical fiber of the light receiving means a position near the light propagation direction upstream side of the optical fiber than the light receiving means Is provided with a bending means for bending at a bending radius of 10 mm or more .

  According to the optical fiber core wire contrast method and the optical fiber core wire contrast device using the same according to the present invention, even if the optical fiber core wire has a greatly improved bending loss characteristic, the core wire contrast work can be easily performed. It can be carried out.

  Embodiments of an optical fiber core wire comparison method and an optical fiber core wire contrast device using the same according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of an optical fiber core wire contrast device, FIG. 2 is a procedure flow diagram of an optical fiber core wire contrast method, and FIG.

  As shown in FIG. 1, a holding stand 11, which is a holding unit that holds an arbitrary optical fiber core 100 selected from a plurality, has a holding groove 11 a that holds the optical fiber core wire 100 inserted therein. Is formed.

  On one side of the holding table 11, there is provided an ultrasonic oscillator 12 which is an ultrasonic wave irradiation means for irradiating the optical fiber core wire 100 held in the holding groove 11 a of the holding table 11 with ultrasonic waves. It has been. The optical fiber core wire 100 held in the holding groove 11 a of the holding table 11 on the other side of the holding table 11, that is, downstream of the ultrasonic oscillator 12 in the light propagation direction of the optical fiber core wire 100. A light receiver 13 is provided as a light receiving means for detecting light leaking from the.

  The light receiver 13 is electrically connected to the input unit of the control device 14. The ultrasonic oscillator 12 is electrically connected to the output unit of the control device 14. A display device 15 which is a display means is electrically connected to the output unit of the control device 14, and the control device 14 controls the operation of the ultrasonic oscillator 12 and information from the light receiver 13. Based on the above, the received light amount detected by the light receiver 13 is displayed on the display device 15 (characters, images, sounds, etc.), and at the same time, the optical fiber core wire 100 held on the holding base 11 is the target. It is possible to determine whether the optical fiber is an optical fiber and display the result on the display device 15 (characters, video, audio, etc.) (details will be described later).

  In the present embodiment, the control device 14, the display device 15 and the like constitute a determination unit.

  Next, an optical fiber core contrast method using the optical fiber core contrast device 10 according to this embodiment will be described.

  As shown in FIG. 2, first, light is propagated in a target optical fiber core (S1). Then, an arbitrary optical fiber core wire 100 is selected from a plurality of optical fiber core wires at the work site, and the optical fiber core wire 100 is connected to the holding groove of the holding base 11 of the optical fiber core wire contrast device 10. 11a is inserted and held (S2).

  Next, when the control device 14 is operated, the ultrasonic oscillator 12 oscillates ultrasonic waves and irradiates the optical fiber core wire 100 held in the holding groove 11a of the holding table 11 with ultrasonic waves (S3). ).

  The optical fiber core wire 100 irradiated with ultrasonic waves is excited to generate periodic vibration (displacement), and a diffraction grating (long-period grating) 101 is formed therein as shown in FIG. When the light 1 propagates through the optical fiber core wire 100 in which such a diffraction grating 101 is formed, a part of the light 1 is diffracted by the diffraction grating 101 and the propagation angle is converted (mode conversion). Thus, the clad mode light 1 a is transmitted through the clad of the optical fiber 100 and leaks out of the optical fiber 100.

  Note that the remaining light 1 that has not been diffracted by the diffraction grating 101 and whose propagation angle has not been converted (mode conversion) continues to propagate further in the optical fiber core wire 100 as it is (propagation mode). .

  As described above, the light 1a leaked from the optical fiber core wire 100 held in the holding groove 11a of the holding table 11 is detected by the light receiver 13 (S4).

  The control device 14 causes the display device 15 to display the received light amount detected by the light receiver 13 based on information from the light receiver 13 (characters, images, sounds, etc.) and also the light receiver 13. When the received light amount detected by the light receiver 13 is equal to or greater than the threshold value (S6), the optical fiber core held by the holding stand 11 is compared with the received light amount detected in step S5 (S5). It is determined that the line 100 is the target optical fiber core wire (S7), and the result is displayed on the display device 15 (characters, video, audio, etc.).

  On the other hand, when the amount of received light detected by the light receiver 13 is not equal to or greater than the threshold value, that is, when the amount of received light detected by the light receiver 13 is less than the threshold value, the control device 14 uses the information from the light receiver 13. Based on this, it is determined that the light 1 is not propagated to the optical fiber core 100 held by the holding base 11, that is, the optical fiber core 100 held by the holding base 11 is not the target optical fiber core. A determination is made (S8), and the result is displayed on the display device 15 (characters, video, audio, etc.).

  Based on the determination result, an arbitrary new optical fiber core 100 is again selected from the plurality of optical fiber cores, and the current optical fiber core 100 held by the holding base 11 is replaced with a new one. The optical fiber core 100 selected in (1) is held in the holding groove 11a of the holding table 11 (S9).

  Hereinafter, by repeating the above-described operation, a target optical fiber core wire can be specified from a plurality of optical fiber core wires.

  In other words, conventionally, the light 1 propagating in the target optical fiber core 100 by bending the optical fiber core 100 is leaked from the bent portion of the optical fiber core 100 of interest. In this embodiment, it is determined whether or not an arbitrary optical fiber core wire 100 is a target optical fiber core wire. However, in this embodiment, any optical fiber core wire is detected. Detecting whether or not the clad mode light 1a of the light 1 propagating in the target optical fiber core leaks from any optical fiber core 100 by irradiating 100 with ultrasonic waves Thus, it is determined whether or not any of the optical fiber cores 100 is a target optical fiber core wire.

  For this reason, in this embodiment, even if the optical fiber core wire 100 is not bent, the target optical fiber core wire can be found from a large number of optical fiber core wires at the work site.

  Therefore, according to the present embodiment, not only an optical fiber core having a conventional general bending loss characteristic but also an optical fiber core which has been attracting attention recently and has greatly improved the bending loss characteristic. However, it is possible to easily perform the cord contrast work.

  Moreover, since the optical fiber core wire 100 is not bent, it is possible to prevent damage to the optical fiber core wire 100 due to bending.

  Incidentally, since the diffraction grating (long-period grating) 101 changes according to the wavelength (frequency) of the ultrasonic wave, the size of the propagation angle converted by diffraction can be set by the wavelength (frequency) of the ultrasonic wave. That is, if the propagation constant of the light 1 propagating in the optical fiber core is β and the propagation constant of the clad mode light 1a of the light 1 is βcl, a part of the light 1 propagating in the optical fiber core is The wavelength Λ of the ultrasonic wave required for conversion into the clad mode light 1a can be set based on the following equation (1).

Λ = 2π / (β-βcl) (1)

  Specifically, the light 1 propagating in a general single-mode optical fiber core is normally in the communication band band (1260 to 1625 nm) or U band band (1625 to 1650 nm), and thus propagates. As shown in FIG. 4 showing the relationship between the wavelength of the light to be coupled and the wavelength of the ultrasonic wave that can be coupled, if the ultrasonic wave has a wavelength of 0.5 to 1.0 mm, the light 1 in the above wavelength band is switched to the cladding mode. This is very preferable because it can be converted efficiently.

  Here, the general outer diameter size of the optical fiber core is either 0.25 mm, 0.5 mm, or 0.9 mm, and the wavelength of the ultrasonic wave is the above-described general outer diameter of the optical fiber core. Since it is equal to or larger than the diameter size, even if the ultrasonic wave having the above wavelength is excited from the outside of the coated optical fiber core, the entire optical fiber can be perturbed by the ultrasonic wave.

  Also, other than the general single-mode optical fiber core, for example, an optical fiber core having an arbitrary refractive index profile, an optical fiber core having a pure silica core, or a cladding region with a plurality of holes Even in an optical fiber core or the like that forms the optical fiber, the difference (β−βcl) between the propagation constant β of the light 1 propagating in the optical fiber core and the propagation constant βcl of the clad mode light 1a of the light 1 Is sufficiently small with respect to the wavelength of the ultrasonic wave, and can be applied in the same manner as described above.

  For example, as shown in FIG. 5, a holding groove 21a having a bent portion 21aa which is a bending means for bending the optical fiber core wire 200 in the vicinity of the light receiver 13 on the upstream side in the light propagation direction from the light receiver 13. Since the optical fiber core line contrast device 20 formed on the holding base 21 has a bending loss larger than that of the light 1 in the propagation mode, the light 1a converted into the cladding mode is bent at the bent portion 21aa. This is preferable because it easily leaks from the bent portion of the optical fiber core 200 and is easily received by the light receiver 13.

  At this time, if the bending radius of the bent portion 21aa of the holding groove 21a of the holding base 21 is set to 10 mm or more, the influence on the light 1 propagating in the optical fiber core wire 200 can be reduced. preferable.

  The optical fiber core wire comparison method and the optical fiber core wire contrast device using the same according to the present invention are extremely effective when applied when conducting an optical continuity test in the construction or operation of an optical line in an optical transmission system. Therefore, it can be used extremely beneficially in industry.

It is a schematic block diagram of embodiment of the optical fiber core wire contrast device which concerns on this invention. It is a procedure flow figure of an embodiment of an optical fiber core line contrast method concerning the present invention. It is an operation explanatory view. It is a graph showing the wavelength of the ultrasonic wave which can be converted into a cladding mode with respect to the wavelength of propagating light. It is a schematic block diagram of other embodiment of the optical fiber core wire contrast device which concerns on this invention.

Explanation of symbols

1 Light (propagation mode)
1a light (clad mode)
DESCRIPTION OF SYMBOLS 10 Optical fiber core wire contrast device 11 Holding stand 11a Holding groove 12 Ultrasonic oscillator 13 Light receiver 14 Control device 15 Display device 20 Optical fiber core wire contrast device 21 Holding stand 21a Holding groove 21aa Bending part 100,200 Optical fiber core wire 101 Diffraction grating (long period grating)

Claims (2)

An optical fiber core comparison method for identifying a target optical fiber core from a plurality of optical fiber cores that do not leak light even if bent ,
Any optical fiber to be irradiated with ultrasonic waves of a wavelength of 0.5~1.0mm the light propagation direction upstream side of the bent portion of the optical fiber with bending the above bending radius 10mm the By forming a diffraction grating inside the optical fiber core wire, whether or not the light propagating in the target optical fiber core wire leaks from the bent portion of any optical fiber core wire. detecting and, optionally of the optical fiber is an optical fiber control method characterized by determining whether the said optical fiber of interest. An optical fiber core contrast device that identifies a target optical fiber core from a plurality of optical fibers that do not leak light even when bent ,
Holding means for holding any optical fiber core; and
An ultrasonic wave is formed in the optical fiber core by irradiating ultrasonic waves having a wavelength of 0.5 to 1.0 mm to the optical fiber core provided in the holder and held by the holder. Sound wave irradiation means;
Light reception that is provided in the holding means so as to be located downstream of the ultrasonic irradiation means in the light propagation direction of the optical fiber core and detects light leaking from the optical fiber core held by the holding means. Means,
Determination means for determining whether the optical fiber core held by the holding means is a target optical fiber core based on information from the light receiving means ; and
The holding means includes bending means for bending the optical fiber core wire at a position near the light receiving means upstream of the light receiving means upstream of the light receiving means with a bending radius of 10 mm or more. An optical fiber core contrast device.

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