Optical monitor device and optical intensity measurement method

Abstract

The purpose of the present disclosure is to enable measurement of a light intensity beyond the limitations of a measurable intensity of a plurality of light-receiving elements by using a light-receiving unit in which the light-receiving elements are two-dimensionally arrayed.　The present disclosure is an optical monitoring device for detecting the intensity of light propagated through a plurality of optical fibers, the device comprising: an optical component that branches, at a fixed branching ratio, a portion of incident light from the plurality of optical fibers in a first direction, and the rest of said incident light in a second direction, and emits the branched light; and a light-receiving unit that receives the light emitted in the second direction from the optical component. The light-receiving unit has a light-receiving surface of a size capable of receiving all the light emitted in the second direction from the optical component. The light receiving surface has light-receiving elements in a number greater than the optical fibers and arrayed two-dimensionally, and the exposure time of the light-receiving elements is variable.

Description

[Technical Field]

[0001] The present disclosure relates to an optical monitoring device, and more particularly to an optical monitoring device for detecting the intensity of light in an optical transmission device or the like and feeding back the detection result to other components. [Background technology]

[0002] In recent years, the increase in Internet traffic has created a strong demand for increased communication capacity in communication systems. To achieve this, optical fiber 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 optical power propagating through optical fibers is often used to control communication and verify the health of equipment. For example, in access networks, test light is propagated through optical fibers, and the optical power is measured to verify the loss and health of the optical fiber, as well as the fiber optics and connections. In addition, WDM (Wavelength Division Multiplexing) transmission used in core networks requires monitoring of optical power for feedback control.

[0003] For example, technology such as that described in Patent Document 1 is used for monitoring optical power in access networks. Patent Document 1 describes a technology that uses two parallel waveguides to split light at a fixed splitting ratio, which enables measurements of optical signal power and propagation loss in access networks.

[0004] For example, the technology described in Patent Document 2 is used for optical intensity monitoring in WMD transmission. Patent Document 2 describes a technology for simultaneously monitoring the intensity of optical signals from multiple optical fibers by combining optical fibers arranged one-dimensionally with a dielectric multilayer film.

[0005] However, conventional optical monitor devices with an arrangement configuration still have the following problems.

[0006] As optical communications become more widespread and the number of optical fibers in optical facilities / optical cables increases, firstly, in the case of optical monitoring devices that use an optical coupler for each optical fiber, the cost and size increase as the number of fibers increases.Even in the case of optical monitoring devices in which optical fibers and optical intensity sensors are arranged in a one-dimensional array, there is a limit to the array arrangement of optical fibers, and if the number of optical fibers increases beyond that, the cost and size increase accordingly.

[0007] In addition, there is a one-to-one correspondence between the optical fiber and the light intensity sensor, and the sensor and optical fiber must be arranged at the same pitch. Furthermore, the optical fiber must be positioned accurately so that the light is incident on the sensor.

[0008] One possible technique to solve this problem is to use a light-receiving unit in which many light-receiving elements are arranged two-dimensionally, with more elements than the number of optical fibers. Light-receiving units in which many light-receiving elements are arranged two-dimensionally generally have a fine structure manufactured using a semiconductor process. However, the electrical elements contained in such fine light-receiving elements, such as optical sensors, circuit resistors, and capacitors, generally have significantly inferior characteristics in terms of electromotive force, resistance, and sensitivity compared to the light-receiving elements used in Patent Documents 1 and 2. In addition, the ratio Smax / Smin of the maximum measurable intensity Smax to the minimum measurable intensity Smin of the light-receiving element is generally significantly lower compared to the light-receiving elements used in Patent Documents 1 and 2. This poses a problem in that the range of light intensity that can be measured is limited. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 3450104 [Patent Document 2] Patent Publication No. 2004-219523 Summary of the Invention [Problem to be solved by the invention]

[0010] The present disclosure has been made in consideration of these points, and aims to make it possible to measure light intensity beyond the limits of the measurable intensity of a light receiving element by using a light receiving unit in which many light receiving elements are arranged two-dimensionally. [Means for solving the problem]

[0011] The optical monitoring device according to the present disclosure comprises: An optical monitor device for detecting the intensity of light propagating through a plurality of optical fibers, an optical component that splits a part of the incident light from the plurality of optical fibers in a first direction and the rest in a second direction at a constant splitting ratio and outputs the split light; a light receiving unit that receives light emitted in a second direction from the optical component; Equipped with the light receiving unit has a light receiving surface large enough to receive all of the light emitted from the optical component in the second direction, a number of light receiving elements greater than the number of the optical fibers are two-dimensionally arranged on the light receiving surface; The exposure time of the light receiving element is variable.

[0012] The light receiving unit may further include an exposure time setting unit that changes the exposure time so that a ratio Smax / Smin of a maximum intensity Smax to a minimum intensity Smin that can be measured by the light receiving element becomes smaller than a ratio Pmax / Pmin of a maximum intensity Pmax to a minimum intensity Pmin of the light to be measured.

[0013] The optical component may include a single-layer film having a uniform thickness and splitting a portion of the incident light in the first direction and the remainder in the second direction at a constant splitting ratio, an incident-side member provided on the incident side of the single-layer film and having a refractive index different from that of the single-layer film, and an output-side member provided on the output side of the single-layer film and having the same refractive index as that of the incident-side member. In this case, a first refractive index interface between the single-layer film and the incident-side member and a second refractive index interface between the single-layer film and the output-side member may be formed at specific angles with respect to the optical axis of the incident light, and the first direction may be a direction of transmission through the first refractive index interface and the second refractive index interface, and the second direction may be a direction of reflection at the first refractive index interface and the second refractive index interface.

[0014] The optical monitoring device according to the present disclosure comprises: a plurality of incident-side optical fibers 11 arranged two-dimensionally so as to input light to the optical component; a plurality of output-side optical fibers arranged two-dimensionally so as to receive each of the output light beams from the optical component in the first direction; 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:

[0015] The light intensity measurement method according to the present disclosure includes: An optical intensity measurement method for simultaneously measuring the intensity of light propagating through a plurality of optical fibers using an optical monitor device according to the present disclosure, comprising: measuring the intensity of light received by each light receiving element 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 light receiving element in advance; measuring the light intensity of each light receiving element received by the light receiving unit while the plurality of optical fibers are propagating light whose intensity is to be measured; Equipped with The measurement is performed multiple times while changing the exposure time during which the light emitted in the second direction is incident on each light receiving element.

[0016] In the measurement, if the light intensity received by any of the light receiving elements arranged in the range determined by the correspondence relationship is smaller than the minimum intensity Smin of the light receiving element, the exposure time of the light receiving element may be extended. In this case, the exposure time of the light receiving element having an intensity smaller than the minimum intensity Smin may be extended until the light intensity exceeds the minimum intensity Smin in all of the light receiving elements arranged in the range determined by the correspondence relationship or until the number of extensions β reaches a predetermined number. The exposure time is calculated by using the number of extensions β to obtain a value K β It may be defined by T.

[0017] In the measurement, if the light intensity received by any of the light receiving elements arranged in the range determined by the correspondence relationship is greater than the maximum intensity Smax of the light receiving element, the exposure time of the light receiving element may be shortened. In this case, the exposure time of the light receiving element having an intensity greater than the maximum intensity Smax may be shortened until the light intensity falls below the maximum intensity Smax in all of the light receiving elements arranged in the range determined by the correspondence relationship. The exposure time is calculated by using the number of shortenings γ as T / K γ It may be defined as:

[0018] The optical monitoring device of the present disclosure comprises: a plurality of incident-side optical fibers arranged in a two-dimensional array so that light is incident on the optical branching portion; a plurality of output-side optical fibers arranged in a two-dimensional array so as to receive each of the output light beams from the optical branching unit in the first direction; an incident-side optical lens disposed between the optical branching unit and the incident-side optical fiber, and converting each light beam incident on the optical branching unit into a parallel beam; an output optical lens disposed between the optical branching unit and the output optical fiber, for coupling each output light from the optical branching unit to the output optical fiber; The device may also include:

[0019] The above disclosures can be combined as much as possible. [Effects of the Invention]

[0020] According to the present disclosure, when light is received using a light receiving unit in which light receiving elements, the number of which is greater than the number of optical fibers, are arranged two-dimensionally on the light receiving surface, it becomes possible to measure light intensity that exceeds the limit of the measurable intensity of the light receiving elements. [Brief explanation of the drawings]

[0021] [Figure 1] 1 illustrates an example embodiment of an optical monitoring device of the present disclosure. [Figure 2] 1 shows an example of the arrangement of the optical fiber on the input side. [Figure 3] 1 shows an example of the arrangement of light receiving elements in a light receiving section. [Figure 4] 1 illustrates an example of a light intensity measurement method according to the present disclosure. [Figure 5] 1 shows an example of light propagating through a spatial optical system. [Figure 6] 1 illustrates an example embodiment of an optical monitoring device of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present disclosure will be described in detail 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 indicate the same components.

[0023] (First embodiment) The optical monitoring device of this embodiment has the configuration shown in FIG. The optical monitoring device of this embodiment is an optical monitoring device that detects the intensity of light propagating through a plurality of incident-side optical fibers 11, a spatial optical system (30) that splits each incident light (41) from an incident-side optical fiber (11) into a majority of the incident light in a specific first direction and the remainder in another specific second direction at a fixed splitting ratio, and outputs each split light; A plurality of incident-side optical fibers 11 arranged two-dimensionally so as to input light into the spatial optical system 30; a plurality of output-side optical fibers 12 arranged to receive output light 42 outputted in a first direction from the spatial optical system 30; a light receiving unit 5 arranged to receive emitted light 43 emitted in a second direction from the spatial optical system 30; an incident-side optical lens 21 disposed between the spatial optical system 30 and the incident-side optical fiber 11, for converting each incident light from the incident-side optical fiber 11 to the spatial optical system 30 into a 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 each output light from the spatial optical system 30 to the output-side optical fiber 12 corresponding to the input-side optical fiber 11; It has.

[0024] In the present disclosure, the light receiving unit 5 receives the light emitted in the second direction, (i) the light intensity received by the light receiving unit 5; (ii) the light intensity of the incident light from the plurality of incident-side optical fibers 11; (iii) the light intensity of the output light emitted to the plurality of output-side optical fibers 12; At least one of the above can be measured.

[0025] 1 shows an example in which the first direction is the x-axis direction and the second direction is the z-axis direction, but the direction of the reflected light split into the second direction is not fixed at 90 degrees and can be changed as needed. Furthermore, the spatial optical system 30 is not limited to a spatial system, and any optical component having a splitting surface that can split light into two light beams with different directions can be used.

[0026] 1, light from the incident-side optical fiber 11 is converted into parallel light by the incident-side optical lens 21, preventing loss due to diffusion. Furthermore, most of the emitted light 42 is guided to the output-side optical lens 22 by the spatial optical system 30. The output-side optical lens 22 collects the light that has passed through the spatial optical system 30 and couples it to the output-side optical fiber 12. In this way, most of the emitted light 42 emitted from the incident-side optical fiber 11 can be guided to the output-side optical fiber 12 with little loss.

[0027] On the other hand, a portion of the emitted light 43 branched by the spatial optical system 30 is guided to the light receiving unit 5, which is arranged in a different direction from the majority of the emitted light 42. The light receiving unit 5 has a light receiving surface large enough to receive all of the emitted light 43 from the spatial optical system 30. Light receiving elements, the number of which is greater than the number of incident-side optical fibers 11, are two-dimensionally arranged on the light receiving surface of the light receiving unit 5. This makes it possible to measure the intensity of a portion of the light propagating from the incident-side optical fiber 11 to the output-side optical fiber 12.

[0028] FIG. 2 illustrates the arrangement of incident-side optical fibers 11, and FIG. 3 illustrates the arrangement of light-receiving elements on the light-receiving surface of the light-receiving unit 5. M incident-side optical fibers F1-FM are arranged two-dimensionally, four at a constant pitch. N light-receiving elements M1-MN are arranged two-dimensionally, also at a constant pitch. In the present disclosure, the pitch of the incident-side optical fibers F1-FM does not match the pitch of the light-receiving elements M1-MN, and no special alignment is performed. Therefore, when incident light 41 is incident from the incident-side optical fiber F1, an image of emitted light 43 from the incident-side optical fiber F1 is formed on the light-receiving surface of the light-receiving unit 5, as shown in FIG. 3, for example. At this time, the emitted light 43 is detected by light-receiving elements M2-M5, M15-M18, M28-M31, and M41-M44. The light receiving section 5 detects the sum of the light intensities detected by the light receiving elements M2 to M5, M15 to M18, M28 to M31, and M41 to M44 as the light intensity of the outgoing light 43 from the incident-side optical fiber F1.

[0029] 4, in the present disclosure, the light intensity of each of the light receiving elements M1 to MN when light of reference intensity Pr is emitted from the incident side optical fiber F1 is measured by setting the time (hereinafter referred to as exposure time) during which the emitted light 43 is incident on the light receiving unit 5 as a fixed time T (S11), the light is received by the light receiving unit 5 (S12), and the measurement results obtained by receiving the light are recorded (S14). 11 ~Or 1N Similarly, for the incident side optical fibers F2 to FM, the correspondence relationship Or between the incident side optical fibers F2 to FM and the light receiving elements M1 to MN can be obtained. 21 ~Or MN is recorded (S15).

[0030] Here, the light receiving unit 5 of the present disclosure includes an exposure time setting unit 51 that sets the exposure time of each light receiving element, and a recording unit 52 that records the light receiving intensity at each light receiving element. In this way, the exposure time of each light receiving element of the light receiving unit 5 of the present disclosure is variable. For example, the exposure time setting unit 51 shortens or extends the exposure time of the light receiving elements M1 to MN shown in FIG. 3 from T. The recording unit 52 records the light receiving intensity at each light receiving element, taking the exposure time into consideration.

[0031] As a method for changing the exposure time, for example, when the light receiving unit 5 has a capacitor that accumulates the charge flowing through the light receiving element, such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor, a method of controlling the charging time of the capacitor using a switching element provided between the light receiving element and the capacitor can be exemplified. Also, a method of control using a shutter installed in front of the light receiving surface of the light receiving element of the CCD sensor, CMOS sensor, etc. can be used.

[0032] Correspondence Or 11 ~Or MN In the recording, if the light intensity is less than the minimum measurable intensity Smin of the light receiving elements M1 to MN (No in S13), the correct Or 11 ~OrMN For example, this may be the case when light exceeding the minimum intensity Smin is detected only in the light receiving elements M16, M17, M29, and M30 shown in FIG. 3, and the other light receiving elements do not meet the minimum intensity Smin.

[0033] The approximate area of ​​the emitted light 43 on the light-receiving surface of the light-receiving unit 5 can be calculated from the numerical aperture of the incident-side optical fiber 11. Therefore, the exposure time setting unit 51 extends the exposure time until the light-receiving elements M2 to M5, M15 to M18, M28 to M31, and M41 to M44, which are arranged in a range around the light-receiving elements M16, M17, M29, and M30 within the range determined by the above-mentioned area, exceed the minimum intensity Smin.

[0034] At this time, in step S11, the exposure time is extended to KT using an arbitrary value K that is greater than 1 and smaller than the ratio Smax / Smin of the maximum intensity Smax and the minimum intensity Smin. Then, steps S12 to S14 are carried out, and recording is performed again.

[0035] If there is still a record that is below Smin in step S13, the exposure time is further increased to K 2 The recording time is extended to T and recording is performed again (S12 to S14).

[0036] In this way, the exposure time is multiplied by K and recording is repeated until the recording of all the light receiving elements arranged in the range determined by the approximate area of ​​the emitted light 43 exceeds Smin. For example, in the case of the β-th extension, the exposure time is multiplied by K β The recording unit 52 sets the exposure time to KT and K 2 T.K. 3 For T..., the recorded value is 1 / K, 1 / K 2 , 1 / K 3 …and multiply by the reciprocal of the exposure time multiple, Or 11 ~Or MN Record as.

[0037] In this embodiment, the exposure time is extended until the readings of all the light receiving elements M2 to M5, M15 to M18, M28 to M31, and M41 to M44 that the light reaches exceed Smin, but the present disclosure is not limited to this. For example, the exposure time may be extended until the number of extensions β reaches a predetermined number of times.

[0038] Furthermore, since the number of light receiving elements used in this disclosure only needs to be sufficient to solve Equation 3 described below, the number of elements used can be reduced to a level that does not affect accuracy. For example, the number of elements to be used in measurement may be determined in advance, and the measurement may be repeated until the number of elements used exceeds the minimum intensity Smin. In the example of Figure 3, the number of elements may be determined to be four, and the process may proceed to step S14 when the minimum intensity Smin is exceeded in step S13 for light receiving elements M16, M17, M29, and M30.

[0039] Furthermore, by setting the value of K to a value greater than 1 and smaller than the ratio Smax / Smin of the maximum intensity Smax to the minimum intensity Smin, the measurable light intensity ranges can be made to overlap as a result of measurements at multiple exposure times. For example, if Smin = 15 and Smax = 60 at recording time T, then Smax / Smin = 4. Therefore, by setting K = 3, light with a light intensity S = 15 to 60 can be measured at exposure time T, and light with a light intensity S = 5 to 20 can be measured at exposure time KT. Therefore, by combining these two measurements, light with a light intensity S = 3 to 60 can be measured. However, if K = 5, light with a light intensity S = 15 to 60 can be measured at exposure time T, and light with a light intensity S = 1 to 12 can be measured at exposure time KT, but light with a light intensity S = 12 to 15 cannot be measured correctly.

[0040] Correspondence Or 11 ~Or MN In the case of recording, if light with an intensity exceeding the maximum intensity Smax is incident, the exposure time is similarly set to T / K, T / K 2 , T / K 3... and repeat the process until all the records are below Smax. In this way, if the number of times of shortening is γ, in the γth shortening, the exposure time is T / K γ The recording unit 52 sets the exposure time to T / K, T / K 2 , T / K 3 ... are recorded as K, K 2 , K. 3 …and multiply by the reciprocal of the exposure time multiple, Or 11 ~Or MN Record as.

[0041] The correspondence between the incident side optical fibers F1 to FM and the light receiving elements M1 to MN can be expressed as follows.

number

[0042] Next, the input optical fibers F1 to FM are respectively fed with the reference intensities k1 to k M When light is incident twice as much, the light intensities O1 to O2 detected by the light receiving elements M1 to MN are N Record the following.

[0043] O1~O N In the case of recording, if the light intensity is below the minimum intensity Smin, or conversely, if the light intensity is above the maximum intensity Smax, O1 to O2 are recorded by the method shown in FIG. N Record the following.

[0044] Recorded light intensities O1 to O N Since is the sum of the light incident from each of the optical fibers F1 to FM, it is expressed as in Equation 2.

number

[0045] Therefore, the intensity of light incident on the light receiving unit 5 from each of the optical fibers F1 to FM is expressed by Equation 3.

number

[0046] Since the branching ratio of the spatial optical system 30 is constant, for example, if it is α:1, it can be estimated that the light intensity incident from the incident-side optical fiber 11 is expressed by Equation 4, and the light intensity propagated to the output-side optical fiber 12 is expressed by Equation 5.

number

number

[0047] The light intensity measurement method of the present disclosure includes: The correspondence relationship expressed by Equation 1 is obtained in advance, While the incident-side optical fiber 11 is propagating light whose intensity is to be measured, the light intensity is measured by the light-receiving unit 5 using Equation 3, The light intensity of the incident light 41 from the incident side optical fiber 11 is measured using Equation 4, The light intensity of the output light 42 propagated to the output side optical fiber 12 is measured using Equation 5.

[0048] The light intensity is measured by the light receiving unit 5 by detecting the light intensity received by each light receiving element when light is emitted from each incident-side optical fiber 11. In this embodiment, the correspondence between the incident-side optical fibers 11 and each light receiving element is acquired in advance. Therefore, the intensity of light propagating through the incident-side optical fibers 11 can be measured collectively based on the correspondence.

[0049] Here, in the light intensity measurement method of the present disclosure, in the measurement of the light intensity at the light receiving unit 5, the correspondence relationship Or 21 ~Or MNFor example, when detecting the light intensity of each light-receiving element received by the light-receiving unit 5 while the incident-side optical fiber 11 and the output-side optical fiber 12 are propagating light whose intensity is to be measured, the light-receiving unit 5 performs measurement multiple times while changing the exposure time during which the output light 43 to the light-receiving unit 5 is incident on each light-receiving element.

[0050] When light whose intensity is to be measured is propagating, it is unknown from which incident-side optical fiber 11 the incident light will be incident. Therefore, the exposure time setting unit 51 determines which incident-side optical fiber 11 the incident light is incident from based on the position of the light-receiving element that receives the outgoing light during the first light reception at the light-receiving unit 5, determines the range of the light-receiving elements for each incident-side optical fiber 11 receiving the incident light based on the correspondence relationship expressed by Equation 1, and if the light intensity received by any of the light-receiving elements included in the determined range is less than the minimum intensity Smin, extends the exposure time of each light-receiving element provided in the light-receiving unit 5, and performs a second light reception at the light-receiving unit 5. The exposure time is changed and measurement is repeated until the light intensity exceeds the minimum intensity Smin for all of the light-receiving elements arranged in the predetermined range, or the number of extensions β reaches a predetermined number. The extended exposure time is K β It may be defined by T.

[0051] The exposure time setting unit 51 determines from which incident-side optical fiber 11 the incident light is incident based on the position of the light-receiving element that receives the outgoing light when receiving light at the light-receiving unit 5 for the first time, and determines the range of the light-receiving element for each incident-side optical fiber 11 receiving the incident light based on the correspondence relationship expressed by Equation 1. If the light intensity received at any of the light-receiving elements included in the determined range is greater than the maximum intensity Smax, the exposure time of each light-receiving element provided in the light-receiving unit 5 is shortened and light is received at the light-receiving unit 5 for the second time. The exposure time is changed and measurement is repeated until the light intensity falls below the maximum intensity Smax at all of the light-receiving elements arranged in the predetermined range. The shortened exposure time is determined by using the number of shortenings γ and calculating T / K γ It may be defined as:

[0052] Here, the predetermined range may be a predetermined number of light receiving elements. Furthermore, since the light receiving elements used in the present disclosure only need to be in a number sufficient to solve Equation 3, the number of elements used can be narrowed down to a range that does not affect accuracy. For example, the number of elements to be used in measurement may be determined in advance, and measurement may be repeated until the number of elements used exceeds the minimum intensity Smin or falls below the maximum intensity Smax.

[0053] 5, the spatial optical system 30 includes a single-layer film 33 having a uniform refractive index and disposed between an incident-side member 30A and an output-side member 30B, both of which are made of a material having a uniform refractive index, and the single-layer film 33 is disposed at a specific angle (45 degrees in the figure) with respect to the optical axis of the incident light 41. As a result, a first refractive index interface 33A between the single-layer film 33 and the incident-side member 30A and a second refractive index interface 33B between the single-layer film 33 and the output-side member 30B are disposed at specific angles with respect to the optical axis of the incident light.

[0054] When the incident-side member 30A and the output-side member 30B have the same refractive index, light beams 42B1 and 42B2 with different wavelengths travel in different directions in the single-layer film 33. Therefore, the incident positions of the light beams 42B1 and 42B2 with different wavelengths on the refractive index interface 33B are different. On the other hand, the light beam incident from the refractive index interface 33B travels in the same direction as the incident-side member 30A due to refraction between the single-layer film 33 and the output-side member 30B. Therefore, even if the optical axes at the input end faces of the output-side optical fibers 12 are arranged parallel to each other, transmitted light can be coupled to the output-side optical fibers 12 regardless of wavelength.

[0055] In this manner, in the present disclosure, the incident position on the refractive index interface 33B differs depending on the wavelength in the single layer film 33. Therefore, when the wavelengths of the output light 43B1 and 43B2 are different, the reflected position on the refractive index interface 33B differs between the output light 43B1 and 43B2. Therefore, in the present disclosure, the correspondence relationship expressed by Equation 1 may be obtained for each wavelength.

[0056] (Effects of the present disclosure) 1, the incident-side optical fiber 11 and the output-side optical fiber 12 are arranged two-dimensionally, and the two-dimensionally arranged light beams are split by the spatial optical system 30. This has the advantage of enabling a smaller size than using an optical monitor device for each optical fiber or an optical monitor device with optical fibers arranged one-dimensionally. In addition, the fewer components make it easier to reduce costs.

[0057] (Second embodiment) In the case of a light receiving unit 5 that has a shutter for each light receiving element, such as a CCD sensor, it is possible to change the exposure time for each light receiving element. Therefore, in this embodiment, the exposure time is extended or shortened for each light receiving element.

[0058] For example, the correspondence relationship Or shown in Figure 4 11 ~Or MN 3 detects light exceeding the minimum intensity Smin, and the other light receiving elements do not meet the minimum intensity Smin, the exposure time setting unit 51 extends the exposure time of the light receiving elements arranged in the range defined by the area around the light receiving elements M16, M17, M29, and M30. For example, the exposure time setting unit 51 extends the exposure time of the light receiving elements M2 to M5, M15 to M18, M28 to M31, and M41 to M44 shown in FIG. 3 excluding the light receiving elements M16, M17, M29, and M30 to KT.

[0059] After extending the exposure time to KT, steps S12 to S14 are performed again, and recording is performed again only for recordings that were below Smin. At this time, in this embodiment, only light receiving elements of the light receiving unit 5, M2 to M5, M15 to M18, M28 to M31, and M41 to M44 shown in Figure 3, excluding light receiving elements M16, M17, M29, and M30, receive light from the incident-side optical fiber F1 again for the extended exposure time.

[0060] If there is still a record that is below Smin in step S13, the exposure time is further increased to K 2Then, in this embodiment, if only the light receiving element M44 among M2 to M5, M15 to M18, M28 to M31, and M41 to M44 shown in FIG. 3 does not meet the minimum intensity Smin, the exposure time setting unit 51 extends the exposure time of only the light receiving element M44.

[0061] In this way, the exposure time is changed and the measurement is repeated until the intensity exceeds the minimum intensity Smin in all of the light receiving elements arranged in the predetermined range. β It may be defined by T.

[0062] In this embodiment, the exposure time of all light receiving elements M2 to M5, M15 to M18, M28 to M31, and M41 to M44 that the light reaches is extended, but the present disclosure is not limited to this. The number of light receiving elements used in the present disclosure only needs to be sufficient to solve Equation 3, which will be described later, so the number of elements used can be reduced to a level that does not affect accuracy. For example, in the example of Figure 3, the number of elements may be set to four, and the exposure time of only light receiving elements M16, M17, M29, and M30 may be extended in step S13.

[0063] Furthermore, if there is a light receiving element with a light intensity greater than the maximum intensity Smax, the exposure time setting unit 51 shortens the exposure time of only the light receiving element with a light intensity greater than the maximum intensity Smax, and performs light reception by the light receiving unit 5 for the second time. The exposure time is changed and measurement is repeated until the intensity falls below the maximum intensity Smax for all of the light receiving elements arranged in a predetermined range. The exposure time to be shortened is calculated by the number of shortenings γ, using T / K γ It may be defined as:

[0064] In the light intensity measurement method of this embodiment, in measuring the light intensity at the light receiving unit 5, 21 ~Or MNFor example, when detecting the light intensity of each light receiving element received by the light receiving unit 5 while the incident-side optical fiber 11 and the outgoing-side optical fiber 12 are transmitting light whose intensity is to be measured, the light receiving unit 5 performs measurement multiple times while changing the exposure time for which the outgoing light 43 to the light receiving unit 5 is incident on each light receiving element for each light receiving element.

[0065] In this embodiment, the exposure time of the light receiving elements whose intensity is less than the minimum intensity Smin is changed and the measurement is repeated until the intensity exceeds the minimum intensity Smin for all the light receiving elements arranged in a predetermined range or the number of extensions β reaches a predetermined number. β It may be defined by T.

[0066] In this embodiment, the exposure time of the light receiving elements with an intensity greater than the maximum intensity Smax is changed and the measurement is repeated until the intensity falls below the maximum intensity Smax for all the light receiving elements arranged in a predetermined range. The exposure time to be shortened is determined by the number of shortenings γ, as expressed by T / K γ It may be defined as:

[0067] Here, the predetermined range may be a predetermined number of light receiving elements. Furthermore, since the light receiving elements used in the present disclosure only need to be in a number sufficient to solve Equation 3, the number of elements used can be narrowed down to a range that does not affect accuracy. For example, the number of elements to be used in measurement may be determined in advance, and measurement may be repeated until the number of elements used exceeds the minimum intensity Smin or falls below the maximum intensity Smax.

[0068] (Third embodiment) FIG. 6 shows a third embodiment of the present disclosure. The incident-side member 30A and the output-side member 30B can be made of a transparent material such as quartz glass. The single-layer film 33 can be formed by placing a spacer 34 of a uniform, predetermined thickness between the incident-side member 30A and the output-side member 30B, creating a gap and utilizing an air layer. The incident-side optical lens 21 and the output-side optical lens 22 can be realized by a collimator incorporating a GRIN (Graded INdex) fiber in a rectangular ferrule used in optical connectors, etc. The incident-side optical fiber 11 and the output-side optical fiber 12, like the incident-side optical lens 21 and the output-side optical lens 22, are also incorporated in rectangular ferrules 23 and 24, respectively. Similar to the incident-side optical lens 21 and the output-side optical lens 22, the optical axes of the incident-side optical fiber 11, the incident-side optical lens 21, the output-side optical fiber 12, and the output-side optical lens 22 can be aligned using a guide pin 25 and a guide hole, as in an optical connector. The light-receiving unit 5 can be realized by a commercially available optical image sensor. By filling the connecting portion other than the single layer film 33 with a refractive index matching material, it is possible to suppress unnecessary Fresnel reflection.

[0069] The above are exemplary embodiments, but the present disclosure is not limited to these. For example, although the single-layer film 33 is an air layer in the present disclosure, the single-layer film 33 may be glass having a lower refractive index than the incident-side member 30A and the exit-side member 30B. Furthermore, the spatial optical system 30 is not limited to a cubic shape, and may be any shape, such as a rectangular parallelepiped. Furthermore, the light-receiving unit 5 may be disposed at any position where it can receive light branched by the spatial optical system 30. For example, the light-receiving unit 5 may be embedded inside the spatial optical system 30.

[0070] 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 mounted in any device used in an optical transmission system, such as a transmitter, receiver, or repeater, and the measurement results at the light receiving unit 5 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.

[0071] The exposure time setting unit 51 and recording unit 52 provided in the optical monitoring device of the present disclosure can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network. The program of the present disclosure is a program for causing a computer to realize the exposure time setting unit 51 or recording unit 52 provided in the optical monitoring device of the present disclosure, and is a program for causing a computer to execute each step provided in the method performed by the optical monitoring device according to the present disclosure. [Explanation of symbols]

[0072] 5: Light receiving part 11: Input optical fiber 12: Output optical fiber 21: Input optical lens 22: Output optical lens 23, 24: Ferrules 25: Guide pin 30: Spatial optical system 30A:Incidence side member 30B: Output side member 33: Single layer membrane 34: Spacer 41: Incident light 42: Most of the emitted light 43: Part of the emitted light 51: Exposure time setting unit 52: Recording department

Claims

1. An optical monitor device for detecting the intensity of light propagating through a plurality of optical fibers, an optical component that splits a portion of the incident light from the plurality of optical fibers in a first direction and the remainder in a second direction at a constant splitting ratio and outputs the split light; a light receiving unit that receives the emitted light, the light receiving unit having a light receiving surface large enough to receive all of the emitted light in the second direction from the optical component, and a plurality of light receiving elements, the number of which is greater than the number of the plurality of optical fibers, arranged two-dimensionally on the light receiving surface; an exposure time setting unit that changes an exposure time during which the emitted light is incident on the plurality of light receiving elements with respect to a predetermined fixed time; a recording unit that records the intensities of light received by the plurality of light receiving elements when light is emitted from the plurality of optical fibers for each optical fiber as a correspondence relationship between the plurality of optical fibers and the plurality of light receiving elements; Equipped with the exposure time setting unit, when measuring the light reception intensities at the plurality of light receiving elements when the emitted light is emitted from the plurality of optical fibers for each of the plurality of optical fibers, changes an exposure time during which the emitted light is incident on the plurality of light receiving elements for each of the plurality of light receiving elements so that the light reception intensities can be measured by the plurality of light receiving elements; the recording unit multiplies the light receiving intensities at the plurality of light receiving elements when the light is emitted from the plurality of optical fibers for each optical fiber by the reciprocal of a multiple obtained by dividing the exposure time at the exposure time setting unit when the light receiving intensities become measurable by the fixed time, and records the result in the correspondence relationship; the correspondence relationship is determined using both light-receiving intensities at the plurality of light-receiving elements when light of a reference intensity is emitted from each of the plurality of optical fibers, and light-receiving intensities at the plurality of light-receiving elements when light of a predetermined k times the reference intensity is emitted from each of the plurality of optical fibers. Optical monitor device.

2. When the number of the plurality of optical fibers is M and the number of the plurality of light receiving elements is N, the correspondence relationship is expressed by a matrix with M rows and N columns, In a state where the plurality of optical fibers are propagating light to be measured in intensity, the light intensities output from the plurality of optical fibers are calculated collectively for each optical fiber using the correspondence relationship of M rows and N columns.

10. The optical monitor device of claim 1.

3. The exposure time setting unit changes the exposure time so that the ratio Smax / Smin of the maximum intensity Smax to the minimum intensity Smin measurable by the plurality of light receiving elements is smaller than the ratio Pmax / Pmin of the maximum intensity Pmax to the minimum intensity Pmin of the light to be measured.

10. The optical monitor device of claim 1.

4. The optical component is a monolayer film having a uniform thickness; an incident-side member provided on an incident side of the single-layer film and having a refractive index different from that of the single-layer film; an exit-side member provided on the exit side of the single-layer film and having the same refractive index as the incident-side member; Equipped with a first refractive index interface between the single layer film and the incident-side member and a second refractive index interface between the single layer film and the output-side member are provided at specific angles with respect to an optical axis of the incident light, the first direction is a direction passing through the first refractive index interface and the second refractive index interface, the second direction is a direction of reflection at the first refractive index interface and the second refractive index interface; 2. The optical monitor device according to claim 1.

5. 5. A light intensity measurement method for simultaneously measuring the intensity of light propagating through a plurality of optical fibers using the optical monitor device according to claim 1, comprising: measuring the intensities of light received by the plurality of light receiving elements when light is emitted from each of the plurality of optical fibers, thereby obtaining the correspondence relationship in advance; measuring the light intensity of the plurality of light receiving elements while the plurality of optical fibers are transmitting light whose intensity is to be measured; Equipped with The measurement is performed multiple times while changing the exposure time during which the emitted light is incident on the multiple light receiving elements. Light intensity measurement method.

6. In the measurement, If the light intensity received by any of the plurality of light receiving elements arranged in the range determined by the correspondence relationship is smaller than a minimum intensity Smin, an exposure time of the light receiving element is extended; When the intensity of light received by any of the plurality of light receiving elements arranged in the range determined by the correspondence relationship is greater than a maximum intensity Smax, the exposure time of the light receiving element is shortened.

6. The light intensity measuring method according to claim 5.

7. In the measurement, extending the exposure time of the light receiving elements having an intensity lower than the minimum intensity Smin until the intensity exceeds the minimum intensity Smin for all of the light receiving elements arranged in the range determined by the correspondence relationship among the plurality of light receiving elements, or until the number of extensions β reaches a predetermined number of times; shortening the exposure time of the light receiving elements having an intensity greater than the maximum intensity Smax until the intensity falls below the maximum intensity Smax in all of the light receiving elements arranged in the range determined by the correspondence relationship among the plurality of light receiving elements; 7. The light intensity measuring method according to claim 6.

8. The exposure time is Using the number of extensions β, K β It is determined by T, Using the number of shortenings γ, T / K γ It is defined in The recording unit When the number of extensions is β, the light intensity of the light receiving element in the correspondence relationship is set to 1 / K β T; When the number of times of shortening is γ, the light intensity of the light receiving element in the correspondence relationship is set to K γ / T.

8. The light intensity measurement method according to claim 7.

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