Crosstalk measurement method

Abstract

This invention provides a crosstalk measurement method that easily measures the crosstalk values ​​of multiple fan-in / fan-out devices. [Solution] The crosstalk measurement method for the fan-in / fan-out device 1 includes a waveguide device 4 containing multiple waveguides and multiple single-core fibers 40, and the crosstalk value XT M The first connection step S12 optically connects multiple waveguides of a known measuring optical device 3 with multiple waveguides of a fan-in / fan-out device 1, and the crosstalk value XT of the optical system consisting of the fan-in / fan-out device 1 and the measuring optical device 3. ij The first crosstalk calculation step S13 calculates the crosstalk value XT calculated in the first crosstalk calculation step S13. ij The crosstalk value XT of the optical device 3 used for measurement. M Using this, the crosstalk value XT of the fan-in / fan-out device 1 D The system includes a second crosstalk calculation step S14 for calculating the following:

Description

Technical Field

[0001] The present invention relates to a crosstalk measurement method.

Background Art

[0002] In recent years, with the increase in information traffic, an expansion of the transmission capacity of optical fibers has been demanded. Multi-core fibers can enhance space utilization efficiency and enable high-capacity information transmission in a limited space. However, since a plurality of cores are arranged in one optical fiber, crosstalk between the cores is likely to occur. Therefore, it is necessary to evaluate such crosstalk.

[0003] The following Patent Document 1 describes a method for measuring crosstalk in a multi-core fiber. In this crosstalk measurement method, cores are selected at each of one end and the other end of the multi-core fiber, the core selected at one end is optically connected to a transmitting optical fiber, and the core selected at the other end is optically connected to a receiving optical fiber, and a crosstalk value is measured. By appropriately changing the combination of the cores selected at one end and the other end of the multi-core fiber and performing such measurement of the crosstalk value, a set of crosstalk values is measured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When measuring the crosstalk value of a multicore fiber, it is conceivable to connect a fan-in / fan-out device to at least one end of the multicore fiber. However, a waveguide such as a multicore fiber may be used in part of the fan-in / fan-out device, and crosstalk can occur in the fan-in / fan-out device itself. Therefore, it is necessary to measure the crosstalk value of the fan-in / fan-out device. However, when measuring the crosstalk value by connecting a single-core fiber to the core of the multicore fiber of the fan-in / fan-out device, as in the crosstalk measurement method of Patent Document 1, the single-core fiber must be reconnected each time the core for which the crosstalk value is being measured is changed. When measuring the crosstalk values ​​of multiple fan-in / fan-out devices, the connection effort becomes even more complicated. For this reason, there is a need for a method to easily measure the crosstalk values ​​of multiple fan-in / fan-out devices.

[0006] Therefore, the present invention aims to provide a crosstalk measurement method that easily measures the crosstalk values ​​of multiple fan-in / fan-out devices. [Means for solving the problem]

[0007] To solve the above problems, aspect 1 of the present invention is a method for measuring crosstalk in a fan-in / fan-out device, comprising a waveguide section including a plurality of waveguides integrated with each other, and a plurality of single-core fibers optically connected individually to the waveguides, comprising a first connection step of optically connecting the plurality of waveguides of a measuring optical device with known crosstalk values ​​to the plurality of waveguides of the fan-in / fan-out device, and a predetermined single-core fiber of the fan-in / fan-out device and a predetermined single-core fiber of the measuring optical device that is optically connected to the predetermined single-core fiber via the waveguide section and the waveguide of the waveguide device, and the method of measuring crosstalk in the fan-in / fan-out device A method for measuring the crosstalk of a fan-in / fan-out device, comprising: a first crosstalk calculation step of measuring the power of light emitted from the other of a predetermined single-core fiber and the predetermined single-core fiber of the measuring optical device, and measuring the power of light emitted from a specific single-core fiber other than the predetermined single-core fiber in the device having the predetermined single-core fiber that emits the light for measurement among the fan-in / fan-out device and the measuring optical device, and calculating the crosstalk value of the optical system consisting of the fan-in / fan-out device and the measuring optical device from the measured light power; and a second crosstalk calculation step of calculating the crosstalk value of the fan-in / fan-out device using the crosstalk value calculated in the first crosstalk calculation step and the crosstalk value of the measuring optical device.

[0008] According to this crosstalk measurement method, by optically connecting the measurement optical device and the fan-in / fan-out device as in the first connection step described above, the crosstalk value of the optical system consisting of the fan-in / fan-out device and the measurement optical device can be calculated according to the above selection by appropriately selecting the single-core fiber into which light is incident and the single-core fiber into which the power of the emitted light is measured. The crosstalk value of the fan-in / fan-out device can be determined from this crosstalk value and the crosstalk value of the measurement optical device. Furthermore, by appropriately changing the above selection, a set of crosstalk values ​​for the fan-in / fan-out device can be obtained. Therefore, the crosstalk value can be obtained by selecting a combination of single-core fibers, without having to reconnect the single-core fibers to the waveguide each time a waveguide for which crosstalk values ​​are to be measured is selected. In particular, the effort of connection is reduced when measuring the crosstalk values ​​of multiple fan-in / fan-out devices. Therefore, according to the crosstalk measurement method of this embodiment, the crosstalk values ​​of multiple fan-in / fan-out devices can be easily measured.

[0009] Aspect 2 of the present invention is a method for measuring the crosstalk of a fan-in / fan-out device according to aspect 1, characterized in that if it is not known that the difference between the crosstalk value of the fan-in / fan-out device and the crosstalk value of the measuring optical device is 10 dB or more, the second crosstalk calculation step is performed, and if it is known that the difference is 10 dB or more, the crosstalk value calculated in the first crosstalk calculation step is used as the crosstalk value calculated in the second crosstalk calculation step.

[0010] The approximate crosstalk value of a fan-in / fan-out device may be known from the design. In this case, if the crosstalk value of the measurement optical device is 10 dB or more smaller than the approximate crosstalk value of the fan-in / fan-out device, the crosstalk in the measurement optical device may be ignored. Therefore, by using the crosstalk calculated in the first crosstalk calculation step as the crosstalk value calculated in the second crosstalk calculation step, the calculation of the crosstalk value of the fan-in / fan-out device can be made easier.

[0011] A third aspect of the present invention is a crosstalk measurement method for a fan-in / fan-out device according to aspect 1, characterized in that the waveguide device comprises a waveguide device body on the single-core fiber side of the measuring optical device and a waveguide device tip on the side connected to the fan-in / fan-out device, the plurality of waveguides at the waveguide device tip are arranged in the same way as the plurality of waveguides at the part of the waveguide portion of the fan-in / fan-out device connected to the measuring optical device, and the mode field diameter of light propagating through the plurality of waveguides at the waveguide device tip is equal to the mode field diameter of light propagating through the plurality of waveguides at the part of the fan-in / fan-out device.

[0012] Because the waveguide device tip has the above configuration, even when the fan-in / fan-out device and the waveguide device tip are brought into contact and the respective waveguides are optically connected, light leakage at the connection point can be suppressed, and crosstalk at the connection point can be suppressed. Therefore, the crosstalk value of the fan-in / fan-out device can be measured more accurately.

[0013] Aspect 4 of the present invention is a method for measuring crosstalk in a fan-in / fan-out device according to aspect 3, characterized in that the portion of the waveguide in the fan-in / fan-out device is a multicore fiber in which the waveguide is the core, and the measuring optical device is manufactured by optically connecting the plurality of waveguides in the waveguide device body of the measuring optical device body, which has the waveguide device body and the plurality of single-core fibers of the measuring optical device, with the core of a multicore fiber having the same configuration as the multicore fiber of the fan-in / fan-out device to form the tip of the waveguide device.

[0014] In this case, the tip of the waveguide device optically connected to the multicore fiber of the fan-in / fan-out device becomes a multicore fiber with the same configuration as the multicore fiber of the fan-in / fan-out device. Therefore, since the multicore fibers are optically connected to each other, the connection is easy, light leakage at the connection point between the fan-in / fan-out device and the measurement optical device can be suppressed, and crosstalk at the connection can be suppressed.

[0015] Aspect 5 of the present invention is a crosstalk measurement method for a fan-in / fan-out device according to aspect 4, further comprising a crosstalk measurement step of measuring the crosstalk value of the fabricated measuring optical device.

[0016] The crosstalk value of a measuring optical device becomes known by measuring its crosstalk value. The method for measuring the crosstalk in this case is not particularly limited.

[0017] Aspect 6 of the present invention is a method for measuring crosstalk in a fan-in / fan-out device according to aspect 3, characterized in that the portion of the waveguide portion of the fan-in / fan-out device is a multicore fiber in which the waveguide is the core, and the measuring optical device is manufactured by a second connection step of optically connecting the plurality of waveguides of the waveguide device body in the measuring optical device body, which has the waveguide device body and the plurality of single-core fibers of the measuring optical device, to the core of a multicore fiber in an optical component having the same configuration as the fan-in / fan-out device, and a cutting step of cutting off a portion of the multicore fiber optically connected to the waveguide device body, so that the portion of the multicore fiber optically connected to the waveguide device body becomes the tip of the waveguide device.

[0018] In some cases, the crosstalk values ​​of mass-produced fan-in / fan-out devices are measured. In such cases, the configurations of mass-produced fan-in / fan-out devices are similar to each other, and one of multiple fan-in / fan-out devices can be used as an optical component.

[0019] Aspect 7 of the present invention is a crosstalk measurement method for a fan-in / fan-out device according to aspect 6, further comprising a crosstalk measurement step of measuring the crosstalk value of the fabricated measuring optical device.

[0020] Similar to embodiment 5, the crosstalk value of the measuring optical device is determined by measuring the crosstalk value of the measuring optical device. The method for measuring the crosstalk in this case is not particularly limited.

[0021] Aspect 8 of the present invention involves, between the second connection step and the cutting step, in which measurement light is incident from either a predetermined single core fiber of the optical component or a predetermined single core fiber of the measuring optical device body that is optically connected to the predetermined single core fiber via the waveguide of the waveguide portion and the waveguide of the waveguide device body, and measuring the power of the light emitted from the other of the predetermined single core fiber of the optical component and the predetermined single core fiber of the measuring optical device body, and having the predetermined single core fiber of the optical component and the measuring optical device body that emits the measurement light. The crosstalk measurement method for a fan-in / fan-out device according to embodiment 7 is characterized by comprising: a third crosstalk calculation step of measuring the power of light emitted from a specific single-core fiber other than the predetermined single-core fiber in the device, and calculating a crosstalk value of the optical system consisting of the optical component and the main body of the measuring optical device from the measured power of light; and a fourth crosstalk calculation step of calculating a crosstalk value of the optical component from which the part of the multi-core fiber has been disconnected, using the crosstalk value calculated in the third crosstalk calculation step and the crosstalk value measured in the crosstalk measurement step.

[0022] In this case, the optical component has a configuration similar to that of a fan-in / fan-out device. Therefore, when the multicore fiber is cut in the cutting step, and a portion of the multicore fiber is separated to serve as the tip of the waveguide device, the resulting optical component is generally similar to that of a fan-in / fan-out device. Consequently, an optical component with a portion of the multicore fiber separated can be used as a fan-in / fan-out device. In this case, the crosstalk value of the optical component with a portion of the multicore fiber separated can be measured using the third and fourth crosstalk calculation steps described above. [Effects of the Invention]

[0023] As described above, the present invention provides a crosstalk measurement method for easily measuring the crosstalk value of a fan-in / fan-out device. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 shows a fan-in / fan-out device according to an embodiment of the present invention. [Figure 2] Figure 2 is a flowchart showing the procedure for measuring crosstalk in a fan-in / fan-out device according to the present invention. [Figure 3] Figure 3 shows the optical device used for measurement. [Figure 4] Figure 4 shows the situation after the first connection step. [Figure 5] Figure 5 shows the relationship between the difference between the crosstalk value of the measuring optical device and the crosstalk value of the fan-in / fan-out device, and the difference between the crosstalk value of the optical system consisting of the fan-in / fan-out device and the measuring optical device and the crosstalk value of the fan-in / fan-out device. [Figure 6] Figure 6 is a flowchart showing the method for fabricating a measurement optical device. [Figure 7] Figure 7 shows the situation after the second connection step. [Modes for carrying out the invention]

[0025] The following examples illustrate embodiments for implementing the crosstalk measurement method for a fan-in / fan-out device according to the present invention, with reference to the accompanying drawings. The embodiments illustrated below are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. Therefore, the present invention can be modified and improved from the following embodiments within the scope of the claims. Note that in the drawings referenced below, the dimensions of each component may be shown differently for the sake of clarity.

[0026] Figure 1 shows a fan-in / fan-out device according to this embodiment. As shown in Figure 1, the fan-in / fan-out device 1 of this embodiment mainly comprises a waveguide section 2 and a plurality of single-core fibers 10. The waveguide section 2 of this embodiment mainly comprises a multi-core fiber 20 and a waveguide substrate 30.

[0027] Each single-core fiber 10 has a core 11 and a cladding that completely surrounds the core and has a lower refractive index than the core. In Figure 1, only the symbol for one core 11 is shown.

[0028] In this embodiment, the multicore fiber 20 is located at one end of the waveguide section 2. The multicore fiber 20 is preferably 2m or longer; however, it may be shorter than 2m. The multicore fiber 20 has a plurality of cores 21 capable of transmitting light, and a cladding surrounding the outer surface of each core 21. The outer surface of the cladding may be surrounded by a coating layer made of resin. In this embodiment, the multicore fiber 20 has four cores 21. In Figure 1, only one core 21 is indicated by its reference numeral.

[0029] Each core 21 is arranged in a 2x2 configuration, that is, on the vertices of a square centered on the central axis of the multicore fiber 20, parallel to each other along the longitudinal direction of the multicore fiber 20, and integrated by cladding. The refractive index of the cores 21 is higher than that of the cladding, and each core 21 is capable of transmitting light. Therefore, each core 21 is a waveguide, and the multicore fiber 20 is part of a waveguide section 2 having multiple parallel optical waveguides. Note that in Figure 1, the cores 21 are depicted as being arranged in a planar configuration to avoid complexity in the drawing.

[0030] In this embodiment, the core 21 is made of silica glass to which a dopant that increases the refractive index, such as germanium (Ge), is added, and the cladding is made of silica glass without any additives. For example, the core 21 may be made of silica glass without any additives, and the cladding may be made of silica glass to which a dopant that decreases the refractive index, such as fluorine (F), or the core 21 may be made of silica glass to which a dopant that increases the refractive index is added, and the cladding may be made of silica glass to which a dopant that decreases the refractive index is added. Furthermore, the dopant that increases the refractive index and the dopant that decreases the refractive index are not particularly limited.

[0031] In this embodiment, the waveguide substrate 30 is the other end portion of the waveguide section 2. The waveguide substrate 30 in this embodiment is generally rectangular in shape. The waveguide substrate 30 is made of a light-transmitting material. Multiple waveguides 31 are formed within the waveguide substrate 30. Since the multiple waveguides 31 are formed within the waveguide substrate 30, they are integrated with each other. In the waveguide substrate 30 of this embodiment, the waveguides 31 formed within the light-transmitting substrate are formed in a three-dimensional pattern. In this embodiment, the multiple waveguides 31 are arranged on one end and the other end, and the distance between adjacent waveguides is different from each other. In this embodiment, the core 21 of the multicore fiber 20 is optically connected to one end of the waveguide 31. Therefore, one end of each waveguide 31 is arranged in the same way as the arrangement of each core 21 of the multicore fiber 20. Therefore, in this embodiment, the multiple waveguides 31 are arranged in a 2x2 configuration at one end, and the distance between the waveguides 31 is equal to the distance between the cores 21 of the multicore fiber 20. Note that in Figure 1, to avoid complicating the diagram, the waveguides 31 are simplified and shown arranged in a planar configuration.

[0032] Multiple waveguides 31 and multiple cores 21, which are multiple waveguides, are optically connected to form multiple integrated waveguides in the waveguide section 2. The other end of each waveguide 31 is optically connected to the core 11 of the single-core fiber 10. Therefore, one end of each single-core fiber 10 is arranged in the same way as the other ends of the multiple waveguides 31. Consequently, the distance between adjacent waveguides 31 in the waveguide substrate 30 of this embodiment is wider on the other end of the waveguide 31 connected to the single-core fiber 10 than on the one end of the waveguide 31 connected to the multi-core fiber 20. Furthermore, the arrangement of the waveguides 31 in this embodiment differs between the one end and the other end of the waveguide 31. Such waveguides 31 can be formed by irradiating a light-transmitting substrate with a femtosecond laser.

[0033] In this specification, "similar" or "equal" means that deviations of a degree equivalent to the manufacturing tolerance of mass-produced products are to be tolerated. For example, when the configuration of multicore fibers is similar or the distance between cores is equal, a deviation of about 1 μm in the cores is to be tolerated. Similarly, when the mode field diameters of the light are equal, a deviation of about 1 μm in the mode field diameters of the compared light is to be tolerated. Furthermore, "optically connected" means that an optical path is formed, for example, when a waveguide and a core are physically in contact to form an optical path, or when a waveguide and a core are separated and an optical path is formed through space. Two waveguides through which light propagates due to crosstalk are not optically connected.

[0034] Next, we will explain the method for measuring the crosstalk of the fan-in / fan-out device 1 shown in Figure 1.

[0035] Figure 2 is a flowchart showing the procedure for measuring the crosstalk of the fan-in / fan-out device 1. As shown in Figure 2, this crosstalk measurement method includes a first preparation step S11, a first connection step S12, a first crosstalk calculation step S13, and a second crosstalk calculation step S14.

[0036] (First preparation step S11) This step involves preparing the fan-in / fan-out device 1 and the measurement optical device. Figure 3 shows the measurement optical device. As shown in Figure 3, the measurement optical device 3 mainly comprises a waveguide device 4 and a plurality of single-core fibers 40, and is a device with a known crosstalk value. The waveguide device 4 mainly comprises a waveguide device body 5 and a waveguide device tip 6.

[0037] The single-core fiber 40 in this embodiment has the same configuration as the single-core fiber 10 of the fan-in / fan-out device 1, and has a core 41.

[0038] The waveguide device body 5 of this embodiment comprises a waveguide substrate 50 and a multicore fiber 60. The multicore fiber 60 is located at one end of the waveguide device body 5, and the waveguide substrate 50 is located at the other end of the waveguide device body 5. The waveguide substrate 50 of this embodiment has the same configuration as the waveguide substrate 30 and has a plurality of waveguides 51. The multicore fiber 60 of this embodiment has the same configuration as the multicore fiber 20 and has a plurality of cores 61 that function as waveguides. The plurality of waveguides 51 of the waveguide substrate 50 and the plurality of cores 61 of the multicore fiber 60 are optically connected in the same manner as the optical connection between the plurality of waveguides 31 of the waveguide substrate 30 and the plurality of cores 21 of the multicore fiber 20. In this way, the plurality of waveguides 51 of the waveguide substrate 50 and the plurality of cores 61 of the multicore fiber 60 form a plurality of integrated waveguides of the waveguide device body 5.

[0039] The core 41 of the single-core fiber 40 and the plurality of waveguides 51 of the waveguide substrate 50 are optically connected in the same way that the core 11 of the single-core fiber 10 and the plurality of waveguides 31 of the waveguide substrate 30 are optically connected. Therefore, the core 11 of the single-core fiber 10 is optically connected to the waveguide 31 at the other end of the waveguide device body 5. In this way, a measuring optical device body 7 is constructed, in which the cores 41 of the plurality of single-core fibers 40 and the plurality of waveguides of the waveguide device body 5 are individually optically connected.

[0040] The waveguide device tip 6 of this embodiment consists of a multicore fiber 70. The waveguide device tip 6 is the part that is optically connected to the multicore fiber 20 of the fan-in / fan-out device 1. The multicore fiber 70 of this embodiment has the same configuration as the multicore fiber 20 and has a plurality of cores 71 that function as waveguides, which are integrated with each other from one end to the other. The plurality of cores 71 of the multicore fiber 70 are arranged in the same way as the plurality of cores 21 of the multicore fiber 20, which is the part of the fan-in / fan-out device 1 that is connected to the measurement optical device 3. Furthermore, the mode field diameter of the light propagating through the plurality of cores 71 of the multicore fiber 70 is equal to the mode field diameter of the light propagating through the plurality of cores 21 of the multicore fiber 20.

[0041] As described above, in this embodiment, the multicore fiber 60 has the same configuration as the multicore fiber 20, and therefore the multicore fiber 70 has the same configuration as the multicore fiber 60. The multicore fiber 70 and the multicore fiber 60 are connected to each other by fusion splicing or connectors (not shown). For this reason, the multiple cores 71 of the multicore fiber 70 and the multiple cores 61 of the multicore fiber 60 are optically connected.

[0042] The measurement optical device 3, with this configuration, has a similar configuration to the fan-in / fan-out device 1. Therefore, the measurement optical device 3 can be understood as a measurement fan-in / fan-out device.

[0043] Furthermore, as long as the core 61 of the multicore fiber 60 and the core 71 of the multicore fiber 70 are optically connectable, the multicore fiber 70 may have a different configuration from the multicore fiber 60. For example, the inter-core distance of the core 61 of the multicore fiber 60 may be slightly different from the inter-core distance of the core 71 of the multicore fiber 70, and the mode field diameter of the light propagating through the core 61 of the multicore fiber 60 and the mode field diameter of the light propagating through the core 71 of the multicore fiber 70 may be different from each other. Also, as long as the core 71 of the multicore fiber 70 and the waveguide of the waveguide substrate 50 are optically connectable, the waveguide substrate 50 may have a different configuration from the waveguide substrate 30. Similarly, the configuration of the single-core fiber 40 may be different from that of the single-core fiber 10.

[0044] (First connection step S12) This step involves optically connecting the fan-in / fan-out device 1 and the measurement optical device 3. Figure 4 shows the setup after this step. Figure 4 also shows that the light source 100 and light receiving devices 201 and 202 are further connected after this step.

[0045] As shown in Figure 4, in this step, the multicore fiber 70, which serves as the tip 6 of the waveguide device, and the multicore fiber 20 are optically connected. At this time, the multiple cores 71 of the multicore fiber 70 and the multiple cores 21 of the multicore fiber 20 are aligned to face each other. As a result, the multiple waveguides in the waveguide device 4 of the measurement optical device 3 and the multiple waveguides in the waveguide section 2 of the fan-in / fan-out device 1 are optically connected. If this connection is made by fusion splicing, light leakage can be suppressed at the connection section 8, and crosstalk at the connection section 8 can be suppressed. Also, if this connection is made by a connector (not shown), optical connection and disconnection can be easily performed. Thus, as shown in Figure 4, the fan-in / fan-out device 1 and the measurement optical device 3 are connected at the connection section 8.

[0046] (First crosstalk calculation step S13) This step involves injecting light for measurement from one of the following: a predetermined single-core fiber 10 of the fan-in / fan-out device 1 and a predetermined single-core fiber 40 of the measuring optical device 3, which is optically connected to the predetermined single-core fiber 10 via the waveguide of the waveguide section 2 and the waveguide of the waveguide device 4; measuring the power of the light emitted from the other of the predetermined single-core fiber 10 of the fan-in / fan-out device 1 and the predetermined single-core fiber 40 of the measuring optical device 3; measuring the power of the light emitted from a specific single-core fiber other than the predetermined single-core fiber in the device having the predetermined single-core fiber that emits the light for measurement; and calculating the crosstalk value of the optical system consisting of the fan-in / fan-out device 1 and the measuring optical device 3 from the measured light power.

[0047] In this step of the embodiment, as shown in Figure 4, one of the multiple single-core fibers 10 is selected, and the light source 100 is optically connected to the selected predetermined single-core fiber 10. In addition, the light receiving device 201 is optically connected to a predetermined single-core fiber 40 that is optically connected to the predetermined single-core fiber 10 optically connected to the light source 100, via the waveguide of the waveguide section 2 and the waveguide of the waveguide device 4. In this example, since the light for measurement is emitted from the predetermined single-core fiber 40 to which the light receiving device 201 is optically connected, the device having the predetermined single-core fiber that emits the light for measurement among the fan-in / fan-out device 1 and the measurement optical device 3 is the measurement optical device 3. In this example, the light receiving device 202 is optically connected to a specific single-core fiber 40 other than this predetermined single-core fiber 40.

[0048] The light source 100 is equipped with, for example, a laser diode and emits light of a predetermined wavelength for measurement. The predetermined wavelength is, for example, 1550 nm. The light source 100 may also emit wavelength-swept light. The light receiving devices 201 and 202 are equipped with, for example, photodiodes and output an electrical signal related to the power of the incident light.

[0049] When light for measurement of a predetermined wavelength is emitted from the light source 100, the light is incident on the core 11 of a predetermined single-core fiber 10 to which the light source 100 is connected. The light incident on the predetermined single-core fiber 10 propagates through a predetermined waveguide 31 of the waveguide substrate 30 and a predetermined core 21 of the multi-core fiber 20, which are optically connected to the core 11 of the single-core fiber 10, and at the connection part 8, it is incident on a predetermined core 71 of the multi-core fiber 70 in the measurement optical device 3, which is optically connected to the predetermined core 21. The light incident on the predetermined core 71 of the multi-core fiber 70 propagates through a predetermined core 61 of the multi-core fiber 60, which is optically connected to the predetermined core 71, and through a predetermined waveguide 51 of the waveguide substrate 50, which is optically connected to the predetermined core 61 of the multi-core fiber 60, and propagates through the core 41 of a predetermined single-core fiber 40, which is optically connected to the predetermined waveguide 51 of the waveguide substrate 50, and is received by the light receiving device 201. The light receiving device 201, upon receiving light, outputs a signal relating to the power of the received light.

[0050] Furthermore, while a portion of the measurement light propagates through the waveguide section 2 of the fan-in / fan-out device 1 and the waveguide device 4 of the measurement optical device, it crosstalks from the predetermined cores 71, 61 and the predetermined waveguide 51 to other cores 71, 61 and other waveguides 51. The crosstalked light propagates through the other cores 71, 61 and other waveguides 51. Therefore, when a portion of the measurement light crosstalks with the cores 71, 61 and waveguides 51 that are optically connected to the single-core fiber 40 to which the light receiving device 202 is connected, the light propagates through these cores 71, 61 and waveguides 51, enters the light receiving device 202 from the core 41 of the single-core fiber 40, and is received by the light receiving device 202. The light receiving device 202, having received the crosstalked light, outputs a signal relating to the power of the received light.

[0051] In this embodiment, the light receiving devices 201 and 202 are electrically connected to the processing device 300. Therefore, the signals related to the power of the light received by the light receiving devices 201 and 201 are input to the processing device 300. The processing device 300 consists of, for example, an integrated circuit such as a microcontroller, IC (Integrated Circuit), LSI (Large-scale Integrated Circuit), or ASIC (Application Specific Integrated Circuit), or an NC (Numerical Control) device. Furthermore, the processing device 300 may or may not use a machine learning machine. The processing device 300 is electrically connected to the memory 301.

[0052] Memory 301 is configured to store information and to be readable. Memory 301 is, for example, a non-transitory recording medium, and semiconductor recording media such as RAM (Random Access Memory) or ROM (Read Only Memory) are preferred, but any type of recording medium such as optical recording media or magnetic recording media may be included. Note that "non-transitory" recording media include all computer-readable recording media except transient propagation signals, and do not exclude volatile recording media. Memory 301 stores information such as a program for the processing unit 300 to calculate the crosstalk value and the crosstalk value of the measuring optical device 3. The processing unit 300 reads the program and information stored in memory 301. Memory 301 may also store information upon instruction from the processing unit 300.

[0053] The processing unit 300 reads a predetermined program from the memory 301, processes the signals input from the photodetectors 201 and 202, and calculates a crosstalk value. This crosstalk value is the crosstalk value of the optical system consisting of the fan-in / fan-out device 1 and the measuring optical device 3.

[0054] The power of the light received by the light receiving device 201 is P i The light power received by the light receiving device 202 and P j Let's assume that the power of light P j XT is the power of the light that crosstalks with the cores 71, 61 and waveguide 51, which are optically connected to the core 41 of the single-core fiber 40 that incident light on the photodetector 202, as the light for measurement propagates through the waveguide and core. ij This is shown by equation (1) below. TIFF0007853507000002.tif13170

[0055] The above program calculates equation (1), and the processing unit 300 performs the calculation of equation (1). In this way, the crosstalk value XT of the optical system consisting of the fan-in / fan-out device 1 and the measuring optical device 3 is obtained. ij The crosstalk value XT is calculated. The processing unit 300 calculates the crosstalk value XT. ij Store the value in memory 301.

[0056] In the above example, one specific single-core fiber 40 is shown. Therefore, when measuring the crosstalk of other single-core fibers 40, the single-core fibers 40 to which the photodetector 202 is optically connected should be any single-core fiber 40 other than the predetermined single-core fiber 40 and the specific single-core fiber 40. Alternatively, there may be multiple specific single-core fibers 40. For example, the photodetector 202 may be optically connected individually to each of the single-core fibers 40 other than the predetermined single-core fiber 40, and the crosstalk value for each may be determined.

[0057] Furthermore, unlike the example in Figure 4, measurement light may be incident from a predetermined single-core fiber 40 of the measurement optical device 3, and the power of the light emitted from a predetermined single-core fiber 10 of the fan-in / fan-out device 1 may be measured. In this case, one of the multiple single-core fibers 40 is selected, and the light source 100 is optically connected to the selected predetermined single-core fiber 40. Also, the light receiving device 201 is optically connected to a predetermined single-core fiber 10 among the multiple single-core fibers 10 that is optically connected to the predetermined single-core fiber 40 via the waveguide of the waveguide device body 5 and the waveguide of the waveguide section 2. In this case, among the fan-in / fan-out device 1 and the measurement optical device 3, the device having a predetermined single-core fiber that emits measurement light is the fan-in / fan-out device 1. Therefore, the light receiving device 202 is optically connected to a specific single-core fiber 10 other than this predetermined single-core fiber 10. Then, the crosstalk value XT is measured in the same manner as in the above embodiment. ij Calculate.

[0058] (Second Crosstalk Calculation Step S14) In this step, the crosstalk value XT calculated in the first crosstalk calculation step S13 ij and the crosstalk value of the measurement optical device 3 are used to calculate the crosstalk value of the fan-in / fan-out device 1.

[0059] In the memory 301 of this embodiment, the crosstalk value XT M of the measurement optical device 3 is stored. The crosstalk value XT M of the measurement optical device 3 is a set of crosstalk values that occur when measuring light is incident on the core 41 of a specific single-core fiber 40 in the waveguide device 4 and crosstalks from the waveguide 51 or cores 61, 71 optically connected to the core 41 of the specific single-core fiber 40 to another waveguide 51 or cores 61, 71. Therefore, in this example, when the processing device 300 propagates the measurement light from the core 41 of a predetermined single-core fiber 40 optically connected to the light receiving device 201, the processing device 300 measures the crosstalk value XT M where the measurement light crosstalks from the core 41 of the single-core fiber 40 optically connected to the light receiving device 202 to the waveguide 51 or cores 61, 71 optically connected thereto. Also, the processing device 300 reads out the program for performing this step and the above crosstalk value XT ij

[0060] Next, the processing device 300 uses the crosstalk value XT ij and the crosstalk value XT M to calculate the crosstalk value XT D of the fan-in / fan-out device 1. The crosstalk value XT D in this case is represented by the following formula (2). TIFF0007853507000003.tif21170

[0061] ​The above program calculates equation (2), and the processing unit 300 performs the calculation of equation (2). Thus, the crosstalk value XT of the fan-in / fan-out device 1 is obtained. D The crosstalk value XT in this case is calculated. D XT is the crosstalk value of light that crosstalks with the waveguide optically connected to the photodetector 202 when light of a predetermined wavelength is propagated through a predetermined single-core fiber 10 of the fan-in / fan-out device 1. The processing unit 300 processes the obtained crosstalk value XT. D It outputs a signal indicating this.

[0062] The waveguides optically connected to the light source 100 and the light receiving device 201, and the waveguides optically connected to the light receiving device 202 are changed as appropriate, and the crosstalk value XT is determined for each combination of the waveguide through which the measurement light propagates and the waveguide through which the light crosstalks. D This is how the crosstalk value XT is determined. D A set is formed.

[0063] Next, the crosstalk value XT of the optical device 3 used for measurement. M The crosstalk value XT of fan-in / fan-out device 1 D We will now explain the case where it is known to be sufficiently small.

[0064] The crosstalk value XT of the optical system consisting of the fan-in / fan-out device 1 and the measuring optical device 3, which is determined in the first crosstalk calculation step S13. ij This is the crosstalk value XT of the optical device 3 used for measurement. M and the crosstalk value XT of fan-in / fan-out device 1 D Using and , it is shown by the following equation (3). TIFF0007853507000004.tif21170

[0065] From equation (3), we obtain the following equation (4). TIFF0007853507000005.tif43170

[0066] The crosstalk of a typical fan-in / fan-out device 1 and a measurement optical device 3 with a configuration roughly the same as fan-in / fan-out device 1 is -10 dB or less. Furthermore, the crosstalk value XT M The crosstalk value XT D If it is sufficiently smaller than the given value, then the following equations (5) and (6) hold. TIFF0007853507000006.tif18170TIFF0007853507000007.tif13170

[0067] Therefore, from equations (4) to (6), we obtain equation (7). TIFF0007853507000008.tif13170

[0068] Therefore, the crosstalk value XT of the measuring optical device 3 M The crosstalk value XT of fan-in / fan-out device 1 D If it is known to be sufficiently small, the crosstalk value XT measured in the first crosstalk calculation step S13 ij Crosstalk value XT of fan-in / fan-out device 1 D It can be considered as such.

[0069] Figure 5 shows the crosstalk value XT of the measurement optical device. M and the crosstalk value XT of fan-in / fan-out device 1 D The difference (XT M -XT D ) and the crosstalk value XT measured in the first crosstalk calculation step S13 ij and the crosstalk value XT of fan-in / fan-out device 1 D The difference (XT ij -XT D This figure shows the relationship with the crosstalk value XT. M and crosstalk value XT D If the difference is -10dB, the crosstalk value XT ij and crosstalk value XT DThe difference is 0.4 dB, which is a negligible difference in the use of fan-in / fan-out device 1. Therefore, the crosstalk value XT of fan-in / fan-out device 1 is... D Crosstalk value XT from the optical device 3 used for measurement M If it is not known that the difference after subtracting is 10 dB or more, perform the second crosstalk calculation step S14. If it is known that the difference is 10 dB or more, perform the crosstalk value XT calculated in the first crosstalk calculation step S13. ij The crosstalk value XT is calculated in the second crosstalk calculation step. D It is preferable to do so. The approximate crosstalk value of the fan-in / fan-out device 1 may be known by design. Also, when the fan-in / fan-out devices 1 are mass-produced, each fan-in / fan-out device 1 will have approximately the same crosstalk value. Therefore, after measuring the crosstalk value of one of the mass-produced fan-in / fan-out devices 1, the approximate crosstalk values ​​of the other fan-in / fan-out devices 1 will become known. In this case, when the approximate crosstalk values ​​of the fan-in / fan-out devices 1 are known, the crosstalk value XT of the measuring optical device 3 M If the crosstalk value is 10 dB or more smaller than the approximate crosstalk value of the fan-in / fan-out device 1, then, as explained above, the crosstalk value XT at the measuring optical device 3 is generally considered to be smaller. M This can be ignored. Therefore, the crosstalk value XT calculated in the first crosstalk calculation step S13 ij The crosstalk value XT is calculated in the second crosstalk calculation step. D By doing so, the crosstalk value XT of the fan-in / fan-out device 1 D This can make the calculation easier.

[0070] Furthermore, from Figure 5, the crosstalk value XT M and crosstalk value XT D If the difference is -15dB, the crosstalk value XT ij and crosstalk value XT DThe difference is almost zero. Therefore, the crosstalk value XT of fan-in / fan-out device 1 D Crosstalk value XT from the optical device 3 used for measurement M If it is known that the difference after subtracting is 15 dB or more, the crosstalk value XT calculated in the first crosstalk calculation step S13 is used. ij The crosstalk value XT of the fan-in / fan-out device 1 is calculated in this step. D It is preferable to do so.

[0071] Next, we will explain how to fabricate the optical device 3 for measurement.

[0072] Figure 6 is a flowchart showing the method for manufacturing the optical device 3 for measurement according to this embodiment. The method for manufacturing the optical device 3 for measurement according to this embodiment comprises a second preparation step S21, a second connection step S22, and a disconnection step S24. In addition, in this embodiment, a third crosstalk calculation step S23 is performed between the second connection step S22 and the disconnection step S24, a crosstalk measurement step S25 is performed after the disconnection step S24, and a fourth crosstalk calculation step S26 is performed after the crosstalk measurement step S25.

[0073] (Second preparation step S21) This step involves preparing the main body 7 of the measurement optical device and optical components having the same configuration as the fan-in / fan-out device 1. As described in the first preparation step S11, the main body 7 of the measurement optical device consists of multiple single-core fibers 40 whose cores 41 are optically connected to the waveguides of the waveguide device main body 5. In other words, this step prepares the main body 7 of the measurement optical device, which has the multi-core fiber 70, which is the tip of the waveguide device 6, removed from the measurement optical device 3. Since the optical components have the same configuration as the fan-in / fan-out device 1, for example, when the fan-in / fan-out device 1 is mass-produced, the optical components can be prepared by using one of the multiple fan-in / fan-out devices 1 as the optical component.

[0074] (Second connection step S22) This step involves optically connecting the multiple waveguides of the waveguide device body 5 in the measurement optical device body 7 to the core of the multicore fiber of the optical component. Figure 7 shows the state after this step. In addition, as with Figure 4, Figure 7 shows that the light source 100 and light receiving devices 201 and 202 are further connected after this step. Furthermore, since the optical component 1A in Figure 7 has the same configuration as the fan-in / fan-out device 1, each component of the optical component 1A is denoted by the same reference numerals as each component of the fan-in / fan-out device 1.

[0075] As shown in Figure 7, in this step of the embodiment, the multicore fiber 60, which is part of the waveguide device body 5 in the measurement optical device body 7, and the multicore fiber 20 of the optical component 1A are optically connected. At this time, the multiple cores 61 of the multicore fiber 60 and the multiple cores 21 of the multicore fiber 20 are aligned to face each other. Thus, the multiple waveguides in the waveguide device body 5 of the measurement optical device body 7 and the multiple waveguides in the waveguide section 2 of the optical component 1A are optically connected. From the viewpoint of suppressing light leakage, fusion splicing is preferable for this connection. Alternatively, this connection may be made using a connector. In this way, as shown in Figure 7, the optical component 1A and the measurement optical device body 7 are optically connected.

[0076] (Third crosstalk calculation step S23) This step involves injecting light for measurement from either a predetermined single-core fiber 10 of optical component 1A or a predetermined single-core fiber 40 of the measuring optical device body 7, which is optically connected to the predetermined single-core fiber 10 via the waveguide of the waveguide section 2 and the waveguide of the waveguide device body 5. The power of the light emitted from the other of the predetermined single-core fiber 10 of optical component 1A or the predetermined single-core fiber 40 of the measuring optical device body 7 is measured, as well as the power of the light emitted from a specific single-core fiber other than the predetermined single-core fiber in the device having the predetermined single-core fiber that emits light, and the crosstalk value of the optical system consisting of optical component 1A and measuring optical device body 7 is calculated from the measured light power.

[0077] In the example shown in Figure 7, the light source 100 is optically connected to a predetermined single-core fiber 10 of the optical component 1A, and the light receiving device 201 is optically connected to a predetermined single-core fiber 40 that is optically connected to the predetermined single-core fiber 10 via the waveguide of the waveguide section 2 and the waveguide of the waveguide device body section 5. Therefore, in this example, since the light for measurement is emitted from the predetermined single-core fiber 40 to which the light receiving device 201 is optically connected, the device among the optical component 1A and the measurement optical device body section 7 that has the predetermined single-core fiber to which the light for measurement is emitted is the measurement optical device body section 7. For this reason, the light receiving device 202 is optically connected to a specific single-core fiber 40 other than this predetermined single-core fiber 40.

[0078] In this step, the optical system used to calculate the crosstalk value differs from the optical system shown in Figure 4 used to calculate the crosstalk value in the first crosstalk calculation step S13, except that the multicore fiber 70, which is the tip of the waveguide device 6, is absent. It is otherwise largely the same as the optical system shown in Figure 4. Therefore, this step in this embodiment is performed in the same manner as the first crosstalk calculation step S13. Thus, the crosstalk value XT' of the optical system consisting of the optical component 1A and the main body of the measuring optical device 7 is calculated. ij This is calculated.

[0079] (Cutting step S24) This step involves disconnecting a portion of the multicore fiber 20 that is optically connected to the waveguide device body 5, so that the remaining portion of the multicore fiber 20 that is optically connected to the waveguide device body 5 becomes the multicore fiber 70 that serves as the waveguide device tip 6. In this step, the multicore fiber 20 is cut at the cutting point 8' shown by the dotted line in Figure 7. Preferably, the cutting point 8' is 2m or more from the waveguide device body 5 in the multicore fiber 20. However, the cutting point 8' may be shorter than 2m from the waveguide device body 5 in the multicore fiber 20. In this way, the portion of the multicore fiber 20 that is disconnected while still optically connected to the waveguide device body 5 becomes the multicore fiber 70 that serves as the waveguide device tip 6, and the measurement optical device 3 is fabricated.

[0080] (Crosstalk measurement step S25) This step is to measure the crosstalk value of the fabricated optical device 3 for measurement. The method for measuring the crosstalk value in this step is not particularly limited. Therefore, this step can be performed, for example, as follows: First, a single-core fiber is connected to a predetermined core 71 of the multi-core fiber 70 of the optical device 3 for measurement, and a light source 100 is connected to the single-core fiber. A light receiving device 201 is connected to a predetermined single-core fiber 40 that is optically connected to the single-core fiber to which the light source 100 is connected, and a light receiving device 202 is connected to another single-core fiber. Then, in the same manner as in the first crosstalk calculation step S13, light for measurement is emitted from the light source 100, the light is received by the light receiving devices 201 and 202, and the processing device 300 calculates the crosstalk value TX ij The crosstalk value of the measuring optical device 3 can be calculated by calculating the crosstalk value in the same way as the calculation for the above crosstalk value TX. M The processing unit 300 then stores the data in the memory 301.

[0081] (Fourth crosstalk calculation step S26) This step involves the crosstalk value XT' calculated in the third crosstalk calculation step S23. ij And the crosstalk value XT of the optical device 3 measured in the crosstalk measurement step S25. M This step involves using the above to calculate the crosstalk value of the optical component 1A, in which a portion of the multicore fiber 20 has been disconnected.

[0082] This step involves the crosstalk value XT' ij The crosstalk value XT measured in the first crosstalk calculation step S13 is the crosstalk value XT ij Therefore, it can be calculated in the same manner as in the second crosstalk calculation step S14. In other words, the crosstalk value XT in the explanation of the second crosstalk calculation step S14 ij Crosstalk value XT' ij This can be reinterpreted as follows. The crosstalk value XT calculated at this time is D Crosstalk value XT' D Therefore, the crosstalk value XT' D This is the crosstalk value of optical component 1A when a portion of the multicore fiber 20 is disconnected.

[0083] Since optical component 1A has the same configuration as fan-in / fan-out device 1, after the multicore fiber 20 is cut in cutting step S24 and a portion of the multicore fiber 20 is separated as the waveguide device tip 6, optical component 1A has a configuration that is generally the same as fan-in / fan-out device 1. Therefore, optical component 1A with a portion of the multicore fiber 20 separated can be used as fan-in / fan-out device 1. Accordingly, the crosstalk value XT' of optical component 1A with a portion of the multicore fiber 20 separated as multicore fiber 70 by the third crosstalk calculation step S23, the crosstalk measurement step S25, and the fourth crosstalk calculation step S26 is calculated. DIt is preferable to measure the crosstalk value XT of the optical component 1A in which a portion of the multicore fiber 20 has been separated as a multicore fiber 70, without performing the third crosstalk calculation step S23, the crosstalk measurement step S25, and the fourth crosstalk calculation step S26. M However, the crosstalk value XT of fan-in / fan-out device 1 D It is preferable to perform the third crosstalk calculation step S23, the crosstalk measurement step S25, and the fourth crosstalk calculation step S26 as they are necessary from the viewpoint of measurement.

[0084] As described above, the crosstalk measurement method for the fan-in / fan-out device 1 of this embodiment includes a first connection step S12 in which a plurality of waveguides of a measurement optical device 3 with a known crosstalk value are optically connected to a plurality of waveguides of the fan-in / fan-out device 1, and a measurement light is incident from one of the single core fiber 10 of the fan-in / fan-out device 1 and the single core fiber 40 of the measurement optical device 3, and the power of the light emitted from the other of the single core fiber 10 of the fan-in / fan-out device 1 and the single core fiber 40 of the measurement optical device 3 is measured, and the crosstalk value XT of the optical system consisting of the fan-in / fan-out device and the measurement optical device is calculated from the power of the light. ij The first crosstalk calculation step S13 calculates the crosstalk value XT ij The crosstalk value XT of the optical device 3 used for measurement. M Using this, the crosstalk value XT of the fan-in / fan-out device 1 is calculated. D The system includes a second crosstalk calculation step S14 for calculating the following:

[0085] According to this crosstalk measurement method, by optically connecting the measurement optical device 3 and the fan-in / fan-out device 1 as in the first connection step S12, the crosstalk value XT of the optical system consisting of the fan-in / fan-out device 1 and the measurement optical device 3 can be determined by appropriately selecting the single-core fiber into which light is incident and the single-core fiber into which the power of the emitted light is measured. ij This crosstalk value XT can be calculated. ij and the crosstalk value XT of the optical device 3 for measurement M Therefore, the crosstalk value XT of the fan-in / fan-out device 1 D Furthermore, by appropriately changing the above selection, the crosstalk value XT of the fan-in / fan-out device 1 can be obtained. D The set can be found. Therefore, the crosstalk value XT D Each time you select a waveguide to obtain the desired crosstalk value XT, you don't need to reconnect the single-core fiber to that waveguide; by selecting a combination of single-core fibers 10 and 40, you can obtain the desired crosstalk value XT. D This can be determined, in particular, the crosstalk value XT of multiple fan-in / fan-out devices 1. D When measuring, the effort required for connection is reduced. Therefore, according to the crosstalk measurement method of this embodiment, the crosstalk value XT of multiple fan-in / fan-out devices 1 can be measured. D It can be easily measured.

[0086] Although the present invention has been described above with reference to the above embodiments, the present invention is not limited to these.

[0087] For example, the arrangement and number of cores in the multicore fiber 20 may differ from those in the above embodiment.

[0088] In the above embodiment, the waveguide section 2 of the fan-in / fan-out device 1 includes a waveguide substrate 30 and a multi-core fiber 20. However, the waveguide section 2 may not have the waveguide substrate 30. In this case, for example, the cores 11 of a plurality of single-core fibers 10 may be individually optically connected to the core 21 of the multi-core fiber 20. Similarly, the waveguide device 4 of the measurement optical device 3 may not have the waveguide substrate 50. In this case, for example, the cores 41 of a plurality of single-core fibers 40 may be individually optically connected to the core 61 of the multi-core fiber 60. Further, a fused-drawn multi-core fiber or a bundle-type optical fiber in which the core-to-core distance is different between one end side and the other end side may be used for at least a part of the waveguide section 2 or the waveguide device 4.

[0089] Also, the waveguide device 4 of the measurement optical device 3 may not have the multi-core fiber 70. In this case, in the crosstalk measurement of the fan-in / fan-out device 1, the end of the multi-core fiber 60 is optically connected to the end of the multi-core fiber 20. Therefore, in this case, it is preferable that the configuration of the multi-core fiber 60 is the same as the configuration of the multi-core fiber 20. That is, the arrangement of the plurality of cores of the multi-core fiber 60 is the same as the arrangement of the plurality of cores 21 of the multi-core fiber 20, and the mode field diameter of the light propagating through the core of the multi-core fiber 60 is preferably equal to the mode field diameter of the light propagating through the core 21 of the multi-core fiber 20. In this case, the measurement optical device 3 cannot be manufactured by the above manufacturing method of the measurement optical device 3. Further, by providing the measurement optical device 3 with a multi-core fiber 70 having the same configuration as the multi-core fiber 20, even when the configuration of the multi-core fiber 60 is different from the configuration of the multi-core fiber 20, light leakage at the connection portion 8 can be suppressed, and the crosstalk value XT D of the fan-in / fan-out device 1 can be suppressed from measurement errors.

[0090] Furthermore, the waveguide section 2 of the fan-in / fan-out device 1 does not necessarily have a multicore fiber 20. In this case, the end of the waveguide substrate 30 is optically connected to the end of the waveguide device 4 of the measurement optical device 3. Also, the waveguide device 4 of the measurement optical device 3 does not necessarily have a multicore fiber 60, 70. In this case, the end of the waveguide substrate 50 is optically connected to the end of the waveguide substrate 30 of the fan-in / fan-out device. In these cases, the measurement optical device 3 cannot be manufactured using the above manufacturing method.

[0091] Furthermore, insofar as the plurality of waveguides of the waveguide section 2 and the plurality of waveguides of the waveguide device 4 are optically connected at the connection section 8, the configuration of the plurality of waveguides of the waveguide section 2 and the configuration of the plurality of waveguides of the waveguide device 4 may differ from each other at the connection section 8. However, in order to suppress crosstalk caused by light leakage at the connection section 8, the crosstalk value XT of the fan-in / fan-out device 1 is controlled. D From the viewpoint of suppressing measurement errors, it is preferable that the configuration of the multiple waveguides in the waveguide section 2 and the configuration of the multiple waveguides in the waveguide device 4 are similar to each other in the connection section 8.

[0092] Furthermore, in the above embodiment, the third crosstalk calculation step S23 and the fourth crosstalk calculation step S26 were performed. However, these steps are not essential.

[0093] Furthermore, in the method for fabricating the measurement optical device 3 of the above embodiment, in the second preparation step S21, an optical component 1A similar to that of the fan-in / fan-out device 1 is prepared, the second connection step S22 is performed, and then the cutting step S24 is performed. However, in the method for fabricating the measurement optical device 3, in the second preparation step S21, a multicore fiber with the same configuration as the multicore fiber 20 of the fan-in / fan-out device 1 may be prepared, and in the second connection step S22, the core of the prepared multicore fiber may be optically connected to the core 61 of the multicore fiber 60 of the measurement optical device body 7. The multicore fiber optically connected to the multicore fiber 60 in this way becomes the multicore fiber 70 as the tip portion 6 of the waveguide device. In this case, the cutting step S24 may be omitted. Also, in this case, if the crosstalk measurement step S25 is performed, this step is performed after the second connection step S22.

[0094] As described above, the multicore fiber 70 may have a different configuration from the multicore fiber 60, as long as the core 61 of the multicore fiber 60 and the core 71 of the multicore fiber 70 are optically connectable. Therefore, the multicore fiber prepared in the second preparation step S21 and connected in the second connection step S22 may have a different configuration from the multicore fiber 60, in the same way as the multicore fiber 70, as long as the cores are optically connectable to each other. In other words, the distance between the cores of the multicore fiber optically connected to the waveguide device body 5 in the second connection step S22 may be slightly different from the distance between the cores 61 of the multicore fiber 60, and the mode field diameter of the light propagating through the core of the multicore fiber may be different from the mode field diameter of the light propagating through the core 61 of the multicore fiber 60. [Industrial applicability]

[0095] As described above, the present invention provides a crosstalk measurement method that easily measures the crosstalk values ​​of multiple fan-in / fan-out devices, and is expected to be used in fields such as optical fiber communication. [Explanation of Symbols]

[0096] 1. Fan-in / fan-out device 1A...Optical components 2. Waveguide section 3. Optical devices for measurement 4. Waveguide devices 5. Waveguide device main body 6. Waveguide device tip 7. Main unit of the optical device for measurement 8. Connection part 10,40···Single-core fiber 20, 60, 70... Multicore Fibers 30, 50... Waveguide substrate 11, 21, 41, 61, 71... Cores (waveguides) 31,51...Waveguides S11...First preparation step S12...First connection step S13...First crosstalk calculation step S14...Second crosstalk calculation step S21...Second preparation step S22...Second connection step S23...3rd Crosstalk Calculation Step S24... Cutting step S25...Crosstalk measurement step S26...4th Crosstalk Calculation Step

Claims

1. A method for measuring crosstalk in a fan-in / fan-out device, comprising a waveguide section including a plurality of waveguides integrated with each other, and a plurality of single-core fibers optically connected individually to the waveguides, A waveguide device including a plurality of waveguides integrated with each other, and a plurality of single-core fibers optically connected individually to the waveguides, comprising a first connection step of optically connecting the plurality of waveguides of a measuring optical device with known crosstalk values ​​to the plurality of waveguides of the fan-in / fan-out device, A first crosstalk calculation step involves injecting light for measurement from either a predetermined single-core fiber of the fan-in / fan-out device or a predetermined single-core fiber of the measuring optical device that is optically connected to the predetermined single-core fiber via the waveguide of the waveguide section and the waveguide of the waveguide device, measuring the power of the light emitted from the other of the predetermined single-core fiber of the fan-in / fan-out device and the predetermined single-core fiber of the measuring optical device, measuring the power of the light emitted from a specific single-core fiber other than the predetermined single-core fiber in the device having the predetermined single-core fiber that emits the light for measurement, and calculating the crosstalk value of the optical system consisting of the fan-in / fan-out device and the measuring optical device from the measured light power. A second crosstalk calculation step calculates the crosstalk value of the fan-in / fan-out device using the crosstalk value calculated in the first crosstalk calculation step and the crosstalk value of the measuring optical device, Equipped with, The waveguide device comprises a waveguide device body on the single-core fiber side of the measuring optical device and a waveguide device tip on the side connected to the fan-in / fan-out device. The plurality of waveguides at the tip of the waveguide device are arranged in the same manner as the plurality of waveguides in the waveguide portion of the fan-in / fan-out device on the side connected to the measuring optical device. The mode field diameter of light propagating through the plurality of waveguides at the tip of the waveguide device is equal to the mode field diameter of light propagating through the plurality of waveguides at the portion of the fan-in / fan-out device. A method for measuring crosstalk in fan-in / fan-out devices, characterized by the following features.

2. The portion of the waveguide in the fan-in / fan-out device and the tip of the waveguide device are both multicore fibers in which the waveguide is the core. A method for measuring crosstalk of a fan-in / fan-out device as described in claim 1.

3. The crosstalk value of the aforementioned measuring optical device is known by measuring the crosstalk value of the aforementioned measuring optical device. The method for measuring crosstalk of a fan-in / fan-out device according to feature 2.

4. A method for measuring crosstalk in a fan-in / fan-out device, comprising a waveguide section including a plurality of waveguides integrated with each other, and a plurality of single-core fibers optically connected individually to the waveguides, A waveguide device including a plurality of waveguides integrated with each other, and a plurality of single-core fibers optically connected individually to the waveguides, comprising a first connection step of optically connecting the plurality of waveguides of a measuring optical device with known crosstalk values ​​to the plurality of waveguides of the fan-in / fan-out device, A first crosstalk calculation step involves injecting light for measurement from either a predetermined single-core fiber of the fan-in / fan-out device or a predetermined single-core fiber of the measuring optical device that is optically connected to the predetermined single-core fiber via the waveguide of the waveguide section and the waveguide of the waveguide device, measuring the power of the light emitted from the other of the predetermined single-core fiber of the fan-in / fan-out device and the predetermined single-core fiber of the measuring optical device, measuring the power of the light emitted from a specific single-core fiber other than the predetermined single-core fiber in the device having the predetermined single-core fiber that emits the light for measurement, and calculating the crosstalk value of the optical system consisting of the fan-in / fan-out device and the measuring optical device from the measured light power. A second crosstalk calculation step calculates the crosstalk value of the fan-in / fan-out device using the crosstalk value calculated in the first crosstalk calculation step and the crosstalk value of the measuring optical device, Equipped with, If it is not known that the difference between the crosstalk value of the fan-in / fan-out device and the crosstalk value of the measuring optical device is 10 dB or more, then the second crosstalk calculation step is performed. If the approximate crosstalk value of the fan-in / fan-out device is known, and the difference obtained by subtracting the crosstalk value of the measuring optical device from the approximate crosstalk value is known to be 10 dB or more, then the crosstalk value calculated in the first crosstalk calculation step is used as the crosstalk value calculated in the second crosstalk calculation step. A method for measuring crosstalk in fan-in / fan-out devices, characterized by the following features.

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