JP7806931B2 - Optical monitor device and optical intensity measurement method - Google Patents

Description

This disclosure relates to an optical monitoring device, particularly an optical monitoring device for detecting the intensity of light in an optical transmission device or the like and feeding back the detection results to other components.

In recent years, with the increase in Internet traffic, there has been a strong demand for increased communication capacity in communication systems. To achieve this, optical fiber-based communication systems are used in access networks between communication centers and user homes, and in core networks connecting communication centers. In optical fiber communication, the detection of the light intensity propagating through the optical fiber is often used to control communication and verify the health of equipment. For example, in access networks, test light is propagated through the optical fiber, and the light intensity is detected to verify the optical fiber's loss, health, core symmetry, and connections. Furthermore, WDM (Wavelength Division Multiplex) transmission used in core networks requires monitoring of light intensity for feedback control.

For optical intensity monitoring in access networks, a technology is used that uses an optical coupler that splits light at a fixed splitting ratio for each optical fiber core using two parallel waveguides (see, for example, Patent Document 1), which makes it possible to measure the intensity and propagation loss of optical signals in the access network.

For optical intensity monitoring in WMD transmission, a technology is used that simultaneously monitors the intensity of optical signals in multiple optical fibers by combining optical fibers arranged in one dimension with optical sensors (see, for example, Patent Document 2).

However, conventional light intensity monitoring configurations still have the following challenges:

As optical communications become more widespread and the number of fiber cores in optical equipment/cables increases, firstly, when an optical coupler is used for each optical fiber core, as in Patent Document 1, costs and size increase as the number of cores increases. Even when optical sensors are arranged in a one-dimensional array to match the number of optical fiber cores, as in Patent Document 2, there is a limit to the array arrangement of optical fibers and optical sensors, and if the number of optical fiber cores increases beyond that, costs and size increase accordingly.

Fresnel reflection in spatial optical systems could be used to achieve this type of light intensity monitoring. However, Fresnel reflection has different reflectances depending on whether p-polarized or s-polarized light is incident. As an example of the difference in reflectance between p-polarized and s-polarized light, Figure 1 shows an example of calculating the incident angle and reflectance of p-polarized and s-polarized light entering air from quartz glass. As shown in Figure 1, if the polarization state of the incident light fluctuates, the branching ratio of the light branched to the optical sensor side fluctuates. For this reason, using Fresnel reflection poses the problem of inaccurate measurements.

Patent No. 3450104 Japanese Patent Application Laid-Open No. 2004-219523

The present disclosure has been made in consideration of these points, and aims to realize an optical intensity measurement method that can measure the optical intensity of an optical signal regardless of the polarization state of the incident optical signal, even in optical fibers with a large number of cores, such as tens of cores.

In order to achieve the above object, the light intensity measurement method of the present disclosure includes:
An optical monitor device for detecting the intensity of light propagating through a plurality of optical fibers,
The optical monitor device of the present disclosure is used.

The optical monitoring device of the present disclosure comprises:
a plurality of branching units that branch the incident light from the plurality of optical fibers that has entered a predetermined incident region into different directions;
a plurality of optical sensors that receive the branched light beams branched by the plurality of branching units, respectively;
Equipped with
the plurality of optical sensors are two-dimensionally arranged with pixels whose number is greater than the number of the plurality of optical fibers, and detect light intensity for each pixel corresponding to an incident position in the incident region;
The light intensities detected by the plurality of optical sensors are summed for each pixel corresponding to the incident position in the incident area.

This disclosure provides multiple optical sensors to detect the optical intensity of each branched light for each pixel corresponding to the incident position in the incident area, and calculates the sum of the optical intensities for each pixel. This allows the present disclosure to measure the optical intensity of incident light for each optical fiber, even for optical fibers with a large number of cores, such as several tens of cores. Here, the polarization axis is expressed in two directions: the y direction and the z direction perpendicular to the x axis, with the direction of light travelling assumed to be the x axis. Therefore, this disclosure provides two branching sections, reflects light in different directions at multiple branching sections, and takes into account the proportion of p-polarized and s-polarized light reflected in each direction, making it possible to measure the optical intensity of an optical signal regardless of the polarization state of the incident optical signal.

The optical monitoring device of the present disclosure comprises:
a first branching unit that branches incident light incident from a predetermined incident region into two beams in a first direction and a second direction;
a first optical sensor that receives the branched light branched in the second direction by the first branching unit and detects the intensity of the light branched by the first branching unit for each incident position in the incident area;
a second branching unit that branches the branched light beam branched in the first direction by the first branching unit into two beams, one in a third direction and the other in the first direction;
a second optical sensor that receives the branched light branched in the third direction by the second branching unit and detects the intensity of the branched light at each incident position in the incident area;
The device may also include:

The optical monitoring device
an optical component having the plurality of branching portions;
a plurality of incident-side optical fibers arranged in a two-dimensional array so as to make light incident on the incident region of the optical component;
a plurality of output-side optical fibers arranged in a two-dimensional array so as to receive each of the output beams from the optical component;
an incident-side optical lens disposed between the optical component and the incident-side optical fiber, and converting each light beam incident on the optical component into a parallel beam;
an output optical lens disposed between the optical component and the output optical fiber, for coupling each output light from the optical component to the output optical fiber;
The device may also include:

The optical component is
a first member having a uniform refractive index;
a first monolayer film in contact with the first member and having a uniform refractive index different from that of the first member;
a second member in contact with the first monolayer film and having the same refractive index as the first member;
a second single-layer film in contact with the second member and having a uniform refractive index different from the refractive indexes of the first member and the second member;
The optical element may further comprise a third member connected to the second single-layer film and the output-side optical lens and having the same refractive index as the first member.
In this embodiment,
the first monolayer film functions as the first branch portion,
the second monolayer film functions as the second branch portion,
a first refractive index interface between the first member and the first single-layer film and a second refractive index interface between the second member and the first single-layer film have a specific first incident angle with respect to the incident light,
a third refractive index interface between the second member and the second single-layer film and a fourth refractive index interface between the third member and the second single-layer film have a specific second incident angle with the incident light,
the first direction is a direction transmitted from the first refractive index interface through the fourth refractive index interface,
the second direction is a direction reflected at the first refractive index interface,
The third direction may be a direction reflected at the third refractive index interface.

The optical monitoring device
a first optical sensor that receives split light from the first monolayer film;
a second optical sensor that receives split light from the second monolayer film;
Equipped with
The light intensity I _Rf of the f-th optical fiber in the plurality of optical fibers may be calculated using a correspondence relationship between the light intensity I _Rf of the f-th optical fiber in the plurality of optical fibers and the average pixel outputs of the first optical sensor and the second optical sensor, which is expressed by equations (16) and (17) described below.

Here, the angle between the incident surface of the first single-layer film and the incident surface of the second single-layer film may be 90 degrees, and the extraction rates of p-polarized light and s-polarized light in the first single-layer film and the second single-layer film may be equal. In this case, R, defined using the extraction rates of p-polarized light and s-polarized light in the first single-layer film and the second single-layer film, may be defined by equation (6) described below, and the average pixel output of the first photosensor and the second photosensor may be calculated based on equation (7) described below.

Here, the angle between the incident surface of the first single-layer film and the incident surface of the second single-layer film may be 90 degrees. In this case, R, which is defined using the extraction rates of p-polarized light and s-polarized light in the first single-layer film and the second single-layer film, may be defined by equation (43) described below, and the average pixel output of the first optical sensor and the second optical sensor may be calculated based on equation (31) described below.

Here, R, which is defined using the extraction rates of p-polarized light and s-polarized light in the first single-layer film and the second single-layer film and the angle between the incident surface of the first single-layer film and the incident surface of the second single-layer film, is defined by equation (53) described below, and the average pixel output of the first optical sensor and the second optical sensor may be calculated based on equation (32) described below.

A light intensity measurement method according to the present disclosure is a light intensity measurement method using an optical monitor device according to the present disclosure,
measuring output values of light intensity detected by each pixel of the plurality of optical sensors when light is emitted from each of the plurality of optical fibers, thereby obtaining a correspondence relationship between the plurality of optical fibers and each of the optical sensors in advance;
a light intensity measurement method for detecting light intensities of pixels included in the plurality of optical sensors while light is propagating through the plurality of optical fibers, and measuring the light intensities of the propagating light through the plurality of optical fibers for each optical fiber based on the correspondence relationship;
When acquiring the correspondence relationship, a sum of output values of the plurality of optical sensors is calculated for each pixel corresponding to an incident position in the incident area.
It has the following characteristics.

When obtaining the correspondence, multiple measurements may be performed to calculate the average output value of each optical sensor for each pixel, and the sum of these average values may be used.

The above disclosures may be combined to the extent possible.

According to the present disclosure, the intensity of an optical signal can be accurately measured regardless of the polarization state of the incident optical signal, even in optical fibers with a large number of cores, such as several tens of cores.

FIG. 10 is a diagram illustrating the relationship between the incident angle and reflectance of s-polarized light and p-polarized light. 1 is a diagram illustrating an optical monitor device according to the present disclosure. 1 is a diagram illustrating an optical monitor device according to the present disclosure. 1 is a diagram illustrating an optical monitor device according to the present disclosure. 1 is a diagram illustrating an optical monitor device according to the present disclosure. 1 is a diagram illustrating an optical monitor device according to the present disclosure. 10 is a diagram illustrating the angle θ formed between the incident surface of the first single-layer film and the incident surface of the second single-layer film. FIG.

Embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are considered to be identical to each other.

(First embodiment)
In order to solve the above problem, the present disclosure provides a light intensity measurement method using an optical monitor device that can be realized by the configuration exemplified in FIG.
The present disclosure provides an optical monitoring device for detecting the intensity of light propagating through a plurality of incident-side optical fibers 11,
a spatial optical system (30) that is an optical component including a plurality of branching units that branch incident light from the plurality of optical fibers (11) that has been incident on a predetermined incident region into different directions;
a plurality of optical sensors 5A and 5B that receive the branched light beams branched by the plurality of branching units, respectively;
Equipped with.

Specifically, the optical monitor device used in the present disclosure is
a spatial optical system (30) that splits and emits a part of the incident light (41) in a specific direction (second direction), a remaining part in another specific direction (third direction), and a majority of the remaining part in yet another specific direction (first direction) at a specific splitting ratio;
an incident-side optical fiber 11 that propagates a plurality of light beams arranged in a two-dimensional array so as to input the light beams into the spatial optical system 30;
a plurality of light-propagating output optical fibers 12 arranged to receive most of the output light 42 from the spatial optical system 30 in a first direction;
a first optical sensor 5A disposed to receive a first portion of the emitted light 43A from the spatial optical system 30 in the second direction;
a second optical sensor 5B disposed to receive a second portion of the emitted light 43B from the spatial optical system 30 in a third direction;
an incident-side optical lens 21 disposed between the spatial optical system 30 and the incident-side optical fiber 11, for converting light incident on an incident region of the spatial optical system 30 into parallel light;
an output-side optical lens 22 that is disposed between the spatial optical system 30 and the output-side optical fiber 12 and efficiently couples the output light from the spatial optical system 30 to the output-side optical fiber 12;
It has.

The optical sensors 5A and 5B have a two-dimensional array of pixels, with more pixels than the number of optical fibers 11, and detect the light intensity for each pixel corresponding to the incident position in the incident region. In this embodiment, a computing device (not shown) calculates the sum of the light intensities detected by the optical sensors 5A and 5B for each pixel corresponding to the incident position in the incident region, and uses the calculated sum of the light intensities for each pixel to calculate the intensity of light propagating through at least one of the optical fibers 11.

As shown in FIG. 2, the spatial optical system 30 includes:
a first member 30A connected to the incident-side optical lens 21 and having a uniform refractive index;
a first single layer film 33A in contact with the first member 30A and having a uniform refractive index different from that of the first member 30A;
a second member 30B in contact with the first single-layer film 33A and having the same refractive index as the first member 30A;
a second monolayer film 33B in contact with the second member 30B and having the same refractive index as the first monolayer film 33A;
a third member 30C connected to the second single-layer film 33B and the output-side optical lens 22 and having the same refractive index as the first member 30A;
It may be configured as follows.

The surface of the first member 30A that is connected to the incident-side optical lens 21 includes an incident region. In the present disclosure, by having such a refractive index for the spatial optical system 30, the relative positions of the parallel light beams incident on the first member 30A from the incident region can be maintained as they are in the incident region. Here, the refractive index of the first single-layer film 33A and the refractive index of the second single-layer film 33B are arbitrary. For example, the refractive index of the first single-layer film 33A and the refractive index of the second single-layer film 33B are lower or higher than the refractive indexes of the first member 30A, the second member 30B, and the third member 30C.

In this embodiment, an example is shown in which the angle θ between the incident surface of the first single-layer film 33A and the incident surface of the second single-layer film 33B is 90 degrees. The first single-layer film 33A functions as a first branching section that branches the incident light into two beams, one in a first direction and one in a second direction. The second single-layer film 33B functions as a second branching section that branches the beam branched in the first direction by the first single-layer film 33A into two beams, one in a third direction perpendicular to both the first and second directions, and one in the first direction.

To facilitate understanding of the spatial optical system 30 shown in Figure 2, Figure 3 shows only one of the two-dimensionally arranged incident-side optical fiber 11 and output-side optical fiber 12. In the following, the light transmitted through the first single-layer film 33A in the x-axis direction will be referred to as the majority of output light 42A, and the light transmitted through the second single-layer film 33B in the x-axis direction will be referred to as the majority of output light 42B. It is also assumed that the optical axis of the incident light 41 is in the x-axis direction.

In Figure 3, the boundary surface between the first member 30A and the first single-layer film 33A is referred to as the first refractive index interface 31A, the boundary surface between the second member 30B and the first single-layer film 33A is referred to as the second refractive index interface 31B, the boundary surface between the second member 30B and the second single-layer film 33B is referred to as the third refractive index interface 31C, and the boundary surface between the third member 30C and the second single-layer film 33B is referred to as the fourth refractive index interface 31D.

Figure 2 shows an example in which the first direction is the x-axis direction, the second direction is the z-axis direction, and the third direction is the y-axis direction, but these directions can be any directions depending on the optical design of the spatial optical system 30.

The spatial optical system 30 includes:
a first refractive index interface 31A and a second refractive index interface 31B that are parallel to each other and have a specific first incident angle with respect to the incident light 41;
a third refractive index interface (31C) and a fourth refractive index interface (31D) that are parallel to each other and are arranged closer to the output-side optical fiber (12) than the first refractive index interface (31A) and the second refractive index interface (31B), have the specific second incident angle with the incident light (41), and have an incident plane orthogonal to the incident planes of the first refractive index interface (31A) and the second refractive index interface (31B);
The first direction in which most of the emitted light 42 is emitted is the direction in which the light passes through the first to fourth refractive index interfaces (31A, 31B, 31C, 31D),
the first incident angle and the second incident angle are equal,
The second direction in which the first portion of the emitted light 43A is emitted is the direction in which the light is reflected at the first refractive index interface 31A,
The third direction in which the second part of the emitted light 43B is emitted is the direction in which the light is reflected at the third refractive index interface 31C.

The third refractive index interface 31C and the fourth refractive index interface 31D may be surfaces formed by rotating the first refractive index interface 31A and the second refractive index interface 31B by 90 degrees in the circumferential direction around the optical axis of the incident light 41.

In Figure 3, the first direction (x direction) is the straight-line direction of incident light 41 incident on the first monolayer film 33A and the direction of travel of most of the emitted light 42A. The second direction (z direction) is the direction of travel of the first portion of the emitted light 43A reflected by the first monolayer film 33A. The third direction (y direction) is the direction of travel of the second portion of the emitted light 43B reflected by the second monolayer film 33B. As described above, by arranging the first monolayer film 33A and the second monolayer film 33B so that the plane containing the first and second directions (xz plane) and the plane containing the first and third directions (xy plane) are perpendicular to each other, the plane of incidence in the first monolayer film 33A and the plane of incidence in the second monolayer film 33B can be made perpendicular.

In the spatial optical system 30 shown in Figures 2 and 3, as described above, the plane of incidence of the first single-layer film 33A and the plane of incidence of the second single-layer film 33B are perpendicular, so p-polarized light in the first single-layer film 33A becomes s-polarized light in the second single-layer film 33B, and s-polarized light in the first single-layer film 33A becomes p-polarized light in the second single-layer film 33B. The first single-layer film 33A and the second single-layer film 33B have the same refractive index and film thickness, so the extraction rate of p-polarized light in the first single-layer film 33A is equal to the extraction rate of p-polarized light in the second single-layer film 33B, and the extraction rate of s-polarized light in the first single-layer film 33A is also equal to the extraction rate of s-polarized light in the second single-layer film 33B.

A method for measuring light intensity using this optical monitor device will be described with reference to FIGS.
As shown in FIG. 3, when the intensities of p-polarized and s-polarized light of the incident light are E _P and E _S , the polarization state of the incident light is expressed by the following equation:

If the extraction rates of p-polarized light and s-polarized light in the first single-layer film 33A and the second single-layer film 33B are R _P and R _S , respectively, the polarization state of light transmitted through the first single-layer film 33A is expressed as follows:

The intensities of light incident on the optical sensors 5A and 5B are expressed by equations (3) and (4), respectively.

At this time, the light intensity to be measured is expressed by the following equation:

When R expressed by equation (6) is defined, equation (7) holds.
(Equation 6)
R _p +R _s -R _p R _s =R (6)
(Equation 7)
I _A + I _B = RI (7)

Therefore, first, J measurements are repeated with only the fth optical fiber emitting light with a light intensity I _Rf . During these measurements, the polarization state of the incident light does not need to be constant and may vary with each measurement. For the jth measurement, if the ratio of the light intensity split into the first monolayer film 33A to the light intensity split into the first monolayer film 33A and the second monolayer film 33B is α _j , the light intensity incident on the optical sensors 5A and 5B can be expressed by the following equation, as shown in FIG. 4 :

The light intensities S _Afij and S _Bfij detected at the ith pixel i of the jth optical sensors 5A and 5B are expressed by equations (10) and (11).
Here, K is the sensor sensitivity of the optical sensors 5A and 5B, k _Afi is the ratio of the light intensity incident on pixel i to the light from the optical fiber f incident on the optical sensor 5A, k _Bfi is the ratio of the light intensity incident on pixel i to the light from the optical fiber f incident on the optical sensor 5B, and n _j is the sensor noise.

The average value (average pixel output) of the output values of the light intensity detected at pixel i of the optical sensors 5A and 5B in J measurements is given by equations (12) and (13).
This makes it possible to determine the average pixel output of pixel i as shown in Fig. 5. However, in equations (12) and (13), J is assumed to be sufficiently large, and the average value of the sensor noise _nj , which is natural noise, is considered to be zero.

The sum of the average pixel outputs of the optical sensors 5A and 5B for all pixels is given by equations (14) and (15).

From the above, the following equation can be obtained, which is the correspondence relationship between the light intensity I _Rf of the fth optical fiber and the average pixel output of the optical sensors 5A and 5B, regardless of the polarization state (α).

Therefore, as a preliminary measurement, the calculation device calculates equations (18) and (19) for each pixel i of the optical sensors 5A and 5B in a state where light of light intensity I _Rf is incident from only one optical fiber in the order of optical fibers 1, 2, ..., f, ..., and creates matrices A _Rfi and B _Rfi in advance, each element of which has this calculated value.

Next, light of different intensities is simultaneously incident from optical fibers 1 to f, and each of the optical sensors 5A and 5B measures this light intensity. The intensities of the light incident on the optical fibers 1 to f are defined as I ₁ to I _f , and the ratio of the average intensities of the extracted light directed toward the optical sensors 5A and 5B during measurement is defined as equation (20).

6 shows an example of the correspondence relationship between the matrix A _Rfi and A _i of the optical sensor 5A. Due to the linearity of light, the output value A _i of the light intensity detected by the optical sensor 5A can be expressed by the following equation.
From this, using the generalized inverse matrix (+), equation (22) is obtained.

Similarly, the equation (23) is obtained for the optical sensor 5B.

As described above, the calculation device of the present disclosure can calculate the light intensities I ₁ to I _f ... to be measured using the output values A _i and B _i of pixel i of the optical sensors 5A and 5B and the matrices A _Rfi and B _Rfi created in advance using equation (24), and can obtain these as measurement results.

As described above, the matrices A _Rfi and B _Rfi created in advance can be created only from the output values of each pixel of each optical sensor 5A and 5B in a previous measurement and the determined light intensity value, and can be created for any polarization state (α). Also, in the measurement, the light intensities I ₁ to I _f ... can be measured using the matrices A _Rfi and B _Rfi for any polarization state (β). This is because equation (7) holds in FIG. 3.

If the S/N ratio of the optical sensors 5A and 5B is sufficiently good and repeated measurements are not necessary, one measurement may be performed instead of J measurements. In this case, the average value obtained by repeated measurements is
Instead, the results of a single measurement, S _Afi and S _Bfi, can be used.

In this embodiment, an example has been shown in which R is defined using the extraction rates of p-polarized light and s-polarized light in the first single-layer film 33A and the second single-layer film 33B as shown in equation (6), but R in this disclosure may also take into account the angle θ between the incident surface of the first single-layer film 33A and the incident surface of the second single-layer film 33B.

Second Embodiment
When the refractive index or film thickness of the first single-layer film 33A and the second single-layer film 33B are different, or when the angle of incidence of the incident light is different, the extraction rates of p-polarized light and s-polarized light may differ. In this case, if the extraction rates of p-polarized light and s-polarized light of the first single-layer film 33A are R _P and R _S , and the extraction rates of p-polarized light and s-polarized light of the second single-layer film 33B are R _P ' and R _S ', the following equation holds:
Here, the definition of R will be described later.

Only p-polarized light and s-polarized light are made incident on each branch portion of the first monolayer film 33A and the second monolayer film 33B using a polarization controller in advance, and R _P , R _S , R _P ', and R _S ' are measured in advance. Based on the results, the average value of the output values of each pixel of the optical sensor 5B (average pixel output) is calculated as (R _P - _{R S} )/{R _P '(1-R _S )-R _S '(1-R _P )}
By using the doubled value, it is possible to use the same light intensity measurement method as in the first embodiment.

(Third embodiment)
Furthermore, in the present disclosure, the angle between the incident surface of the first single-layer film 33A and the incident surface of the second single-layer film 33B may be any angle θ other than 0 degrees and 180 degrees, as shown in Fig. 7 . In this case, the following equation holds:
Here, the definition of R will be described later.

R _P , R _S , R _P ', R _S ', and θ are measured in advance, and based on the results, the average value of the output values of each pixel of the optical sensor 5B (average pixel output) is calculated.
By using the doubled value, it is possible to use the same light intensity measurement method as in the first embodiment.

The above are example embodiments, but the present invention is not limited to these. For example, the spatial optical system 30 is not limited to a cubic shape, and can be any shape, such as a rectangular parallelepiped. Furthermore, the optical sensors 5A and 5B can be positioned in any position where they can receive the light branched by the spatial optical system 30. For example, the optical sensors 5A and 5B may be embedded inside the spatial optical system 30.

The optical monitoring device of the present disclosure can also be used to monitor any light transmitted in an optical transmission system. For example, the optical monitoring device of the present disclosure can be installed in any device used in an optical transmission system, such as a transmitter, receiver, or repeater, and the measurement results from optical sensors 5A and 5B can be used for feedback or feedforward to any component inside or outside the device. Furthermore, the optical monitoring device of the present disclosure can be inserted midway along a transmission line in an optical transmission system to measure the intensity and propagation loss of an optical signal in the transmission line.

(Definition of R in the second embodiment)
When the extraction rates of p-polarized light and s-polarized light in the first single-layer film 33A and the second single-layer film 33B are different, the intensity of light incident on the optical sensor 5B is expressed by the following equation.
Here, the parameters are as follows:
R _P , R _S : extraction rates of p-polarized light and s-polarized light of the first single-layer film 33A. R _P ', R _S ': extraction rates of p-polarized light and s-polarized light of the second single-layer film 33B.

The propagating light intensity I at the time of incidence is expressed by the following equation.

Therefore, R defined below is used.

As a result, the following relationship is obtained using equation (42) for the propagating light intensity I at the time of incidence:

(Definition of R in the third embodiment)
When the angle θ between the incident surface of the first single-layer film 33A and the incident surface of the second single-layer film 33B is not 90 degrees but is an arbitrary angle θ degrees as shown in FIG. 7, the intensity of light incident on the optical sensor 5B is expressed by the following equation:

The propagating light intensity I at the time of incidence is expressed by the following equation.

Therefore, in this embodiment, R defined below is used.

As a result, the following relationship is obtained using equation (52) for the propagating light intensity I at the time of incidence:

This disclosure can be applied to the information and communications industry.

5A, 5B: Optical sensor 11: Incident side optical fiber 12: Emitting side optical fiber 13: Incident side ferrule 14: Emitting side ferrule 15: Guide pin 21: Incident side optical lens 22: Emitting side optical lens 31: Refractive index interface 33A, 33B: Single layer film 34: Spacer 41: Incident light 42: Most of the emitted light 43A, 43B: Part of the emitted light 30: Spatial optical system 30A, 30B, 30C: Members

Claims (8)

An optical monitor device for detecting the intensity of light propagating through a plurality of optical fibers,
a plurality of branching units that branch the incident light from the plurality of optical fibers that has entered a predetermined incident region into different directions;
a plurality of optical sensors that receive the branched light beams branched by the plurality of branching units, respectively;
Equipped with
a first branching portion of the plurality of branching portions branches incident light from the plurality of optical fibers into a specific first direction and a second direction different from the first direction;
a second branching unit among the plurality of branching units branches the branched light branched in the first direction into a third direction perpendicular to both the first direction and the second direction;
a first optical sensor among the plurality of optical sensors receives branched light branched in the second direction;
a second optical sensor among the plurality of optical sensors receives branched light branched in the third direction;
the first optical sensor and the second optical sensor have a number of pixels two-dimensionally arranged that is greater than the number of the plurality of optical fibers, and detect light intensity for each pixel corresponding to an incident position in the incident region;
calculating a sum of the light intensities detected by the first optical sensor and the second optical sensor for each pixel corresponding to an incident position in the incident region, and using the calculated sum of the light intensities of each pixel to calculate the intensity of light propagating through at least one of the plurality of optical fibers;
Optical monitor device. a first member having a uniform refractive index;
a first monolayer film in contact with the first member and having a uniform refractive index different from that of the first member;
a second member in contact with the first monolayer film and having the same refractive index as the first member;
a second single-layer film in contact with the second member and having a uniform refractive index different from the refractive indexes of the first member and the second member;
a third member in contact with the second monolayer film and having the same refractive index as the first member;
an optical component comprising:
a first refractive index interface between the first member and the first single-layer film and a second refractive index interface between the second member and the first single-layer film have a first incident angle with respect to the incident light,
a third refractive index interface between the second member and the second single-layer film and a fourth refractive index interface between the third member and the second single-layer film have a second incident angle with the incident light,
the first monolayer film and the second monolayer film function as the plurality of branch portions;
10. The optical monitor device of claim 1. calculating a light intensity I _Rf of an f- th optical fiber among the plurality of optical fibers using a correspondence relationship between a light intensity I _Rf of an f-th optical fiber among the plurality of optical fibers and average pixel outputs of the first optical sensor and the second optical sensor, which is expressed by the following formula:
3. The optical monitor device according to claim 2.
Furthermore, k _Afi is the ratio of the light intensity incident on the ith pixel i to the light from the optical fiber f incident on the first optical sensor,
k _Bfi is the ratio of the light intensity incident on the ith pixel i to the light from the optical fiber f incident on the second optical sensor,
K is the sensor sensitivity of the first optical sensor and the second optical sensor,
R is a value defined using the extraction rates of p-polarized light and s-polarized light in the first single-layer film and the second single-layer film, and the angle between the incident plane of the first single-layer film and the incident plane of the second single-layer film. wherein R is defined in formula C21;
4. The optical monitor device of claim 3, wherein the average pixel output of the first optical sensor and the second optical sensor is calculated based on equation C22.
where:
I _A and I _B are the light intensities detected by the first and second photosensors,
R _P and R _S are the extraction rates of p-polarized light and s-polarized light in the first monolayer film,
R _P ' and R _S ' are the extraction rates of p-polarized and s-polarized light in the second monolayer film. an angle formed between an incident surface of the first single-layer film and an incident surface of the second single-layer film is 90 degrees;
wherein R is defined by formula C31;
4. The optical monitor device of claim 3, wherein the average pixel output of the first optical sensor and the second optical sensor is calculated based on equation C32.
where:
I _A and I _B are the light intensities detected by the first and second photosensors,
R _P and R _S are the extraction rates of p-polarized light and s-polarized light in the first monolayer film,
R _P ' and R _S ' are the extraction rates of p-polarized and s-polarized light in the second monolayer film. an angle formed between an incident surface of the first single-layer film and an incident surface of the second single-layer film is 90 degrees;
the extraction rates of p-polarized light and s-polarized light in the first single-layer film and the second single-layer film are equal;
wherein R is defined as formula C41;
4. The optical monitor device of claim 3, wherein the average pixel output of the first optical sensor and the second optical sensor is calculated based on equation C42.
R _p +R _s -R _p R _s =R (C41)
I _A + I _B = RI (C42)
Here, I _A and I _B represent the light intensities detected by the first optical sensor and the second optical sensor, and R _P and R _S represent the extraction rates of p-polarized light and s-polarized light in the first single-layer film and the second single-layer film. A method for measuring optical intensity using the optical monitor device according to any one of claims 1 to 6, comprising:
measuring an output value of light intensity detected by each pixel of the plurality of optical sensors when light is emitted from each of the plurality of optical fibers, thereby obtaining in advance a correspondence relationship between each of the plurality of optical fibers and each pixel of the plurality of optical sensors;
detecting the light intensity of each pixel of the plurality of optical sensors while the plurality of optical fibers are propagating light, and measuring the light intensity of the propagating light of the plurality of optical fibers for each optical fiber based on the correspondence relationship;
A light intensity measuring method, characterized in that, in acquiring the correspondence relationship, a sum of output values of the plurality of optical sensors is calculated for each pixel corresponding to an incident position in the incident area. The light intensity measurement method described in claim 7, characterized in that, in obtaining the correspondence, multiple measurements are performed, the average output value of each optical sensor is calculated for each pixel, and the sum of these average values is used.