Optical receiver and optical transceiver

Abstract

To provide an optical receiver etc., capable of obtaining a phase error corresponding to each phase difference between signal light and station emitted light when the phase difference is 0 to 360 degrees while adjusting the phase difference between the signal light and station emitted light.SOLUTION: An optical receiver has: a first port inputting signal light and a second port inputting station emitted light; and an optical circuit which comprises an optical hybrid circuit outputting output light beams different by 90 degrees based upon the signal light and the station emitted light. The optical receiver has a phase adjustment part which is arranged in a first light guide which guides the signal light between the optical hybrid circuit and the first port or a second light guide which guides the station emitted light between the optical hybrid circuit and the second port, and adjusts the phase of the guided light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical receiver and an optical transceiver. [Background technology]

[0002] Fig. 9 is an explanatory diagram showing an example of a conventional test system 200. The test system 200 shown in Fig. 9 includes a test apparatus 210, an optical receiver 220, a first optical fiber F11, and a second optical fiber F12. The test apparatus 210 includes a first light source 211A, a first polarization controller 212A, a second light source 211B, and a second polarization controller 212B.

[0003] The first light source 211A is, for example, a light source that emits a test light corresponding to the signal light. The first polarization controller 212A polarizes the test light corresponding to the signal light from the first light source 211A and outputs the polarized test light to the first optical fiber F11. The first polarization controller 212A controls the polarization of the test light to generate test light of the signal light of TE polarization and TM polarization.

[0004] The second light source 211B is, for example, a light source that emits test light corresponding to the local light. The second polarization controller 212B polarizes the test light corresponding to the local light from the second light source 211B and outputs the polarized test light to the second optical fiber F12. The second polarization controller 212B controls the polarization of the test light to generate the test light of the local light of TE polarization.

[0005] The optical receiver 220 is, for example, an optical IC chip such as a digital coherent optical transceiver. The optical receiver 220 is an optical chip cut out from a wafer. The optical receiver 220 has a first optical port 221A, a second optical port 221B, an optical circuit 222, a first optical waveguide 223A, a second optical waveguide 223B, an electrode wiring 224, and an electrode pad 225. The first optical port 221A is an optical port that is exposed to a chip end face D11, which is a side end of the optical receiver 220, by forming the wafer into a chip, and is optically connected to the first optical fiber F11 to input the signal light from the first optical fiber F11. The second optical port 221B is an optical port that is exposed to a chip end face D11 of the optical receiver 220 by forming the wafer into a chip, and is optically connected to the second optical fiber F12 to input the local light from the second optical fiber F12. The first optical waveguide 223A is an optical waveguide such as a Si waveguide through which signal light is guided between the first optical port 221A and the optical circuit 222. The second optical waveguide 223B is an optical waveguide such as a Si waveguide through which local light is guided between the second optical port 221B and the optical circuit 222. The optical circuit 222 is a circuit such as an optical receiver. The electrode wiring 224 is an electric wiring that applies a voltage to a part of the optical circuit 222. The electrode pad 225 is a pad that is electrically connected to the electrode wiring 224 and applies a voltage to the electrode wiring 224.

[0006] The optical circuit 222 has a PBS (Polarization Beam Splitter) 231 connected to the first optical waveguide 223A, a PR (Polarization Rotator) 232, and a first monitor PD (Photo Detector) 233A. The optical circuit 222 has a first VOA (Variable Optical Attenuator) 234A, a second monitor PD 233B, a second VOA 234B, a 1×2 coupler 235, a first optical hybrid circuit 236A, and a second optical hybrid circuit 236B. The optical circuit 222 has first to fourth PDs 237A to 237D, first to fourth output ports 238A to 238D, fifth to eighth PDs 237E to 237H, and fifth to eighth output ports 238E to 238H.

[0007] The first optical port 221A is formed on the chip end face D11 of the optical receiver 220, and is, for example, an EC of a port that connects to a first optical fiber F11 that inputs signal light. The second optical port 221B is formed on the chip end face D11 in the optical receiver 220, and is, for example, an EC of a port that connects to a second optical fiber F12 that inputs local light.

[0008] The PBS 231 separates the signal light input from the first optical port 221A into two orthogonal polarization states, for example, an X-polarized component which is TE (Transverse Electric) polarization and a Y-polarized component which is TM (Transverse Magnetic) polarization. The PBS 231 outputs the X-polarized component signal light to the first optical hybrid circuit 236A. Furthermore, the PR 232 rotates the Y-polarized component signal light from the PBS 231 by 90 degrees, converts it into a Y-polarized component signal light after polarization rotation, and outputs it to the second optical hybrid circuit 236B. The 1×2 coupler 235 optically branches the local light input from the second optical port 221B, and outputs the TE-polarized local light to the first optical hybrid circuit 236A and the second optical hybrid circuit 236B.

[0009] The first monitor PD 233A is electrically connected to the electrode wiring 224, and detects the power of the signal light guided through the optical waveguide between the PBS 231 and the first optical hybrid circuit 236A in response to a voltage applied to the electrode wiring 224. The first VOA 234A is electrically connected to the electrode wiring 224, and adjusts the power of the signal light guided through the optical waveguide between the PBS 231 and the first optical hybrid circuit 236A in response to a voltage applied to the electrode wiring 224.

[0010] The second monitor PD 233B is electrically connected to the electrode wiring 224, and detects the power of the signal light guided through the optical waveguide between the PR 232 and the second optical hybrid circuit 236B in response to the voltage applied to the electrode wiring 224. The second VOA 234B is electrically connected to the electrode wiring 224, and adjusts the power of the signal light guided through the optical waveguide between the PR 232 and the second optical hybrid circuit 236B in response to the voltage applied to the electrode wiring 224.

[0011] The first optical hybrid circuit 236A causes the local light to interfere with the signal light of the X-polarized component to obtain optical signals of the I and Q components. The I component is an in-phase axis component, and the Q component is an orthogonal axis component. The first optical hybrid circuit 236A outputs the I component signal light of the signal light of the X-polarized component to the first PD 237A and the second PD 237B. The first optical hybrid circuit 236A outputs the first signal light obtained by multiplexing the 0-degree signal light and the 90-degree local light based on the 0-degree signal light and the 0-degree local light to the first PD 237A. The first signal light is a XIp component signal light in which the phase difference between the signal light and the local light is 0 degrees. The first optical hybrid circuit 236A outputs the second signal light obtained by multiplexing the 90-degree signal light and the 0-degree local light based on the 0-degree signal light and the 0-degree local light to the second PD 237B. The second signal light is an XIn component signal light having a phase difference of 180 degrees between the signal light and the local light.

[0012] The first optical hybrid circuit 236A outputs the Q component optical signal of the X polarization component signal light to the third PD 237C and the fourth PD 237D. The first optical hybrid circuit 236A outputs the third signal light obtained by multiplexing the 90 degree signal light and the 90 degree local light based on the 90 degree signal light and the 0 degree local light to the third PD 237C. The third signal light is the XQp component signal light in which the phase difference between the signal light and the local light is 90 degrees. The first optical hybrid circuit 236A outputs the fourth signal light obtained by multiplexing the 180 degree signal light and the 0 degree local light based on the 90 degree signal light and the 0 degree local light to the fourth PD 237D. The fourth signal light is the XQn component signal light in which the phase difference between the signal light and the local light is 270 degrees.

[0013] The first PD 237A electrically converts and gain-adjusts the first signal light XIp of the I component of the X polarization component from the first optical hybrid circuit 236A, and outputs the gain-adjusted electrical signal to the first output port 238A. The second PD 237B electrically converts and gain-adjusts the second signal light XIn of the I component of the X polarization component from the first optical hybrid circuit 236A, and outputs the gain-adjusted electrical signal to the second output port 238B.

[0014] The third PD 237C electrically converts and gain-adjusts the third signal light XQp of the Q component of the X polarization component from the first optical hybrid circuit 236A, and outputs the gain-adjusted electrical signal to the third output port 238C. The fourth PD 237D electrically converts and gain-adjusts the fourth signal light XQn of the Q component of the X polarization component from the first optical hybrid circuit 236A, and outputs the gain-adjusted electrical signal to the fourth output port 238D.

[0015] The relationship of the output light output from the first optical hybrid circuit 236A to the first to fourth PDs 237A to 237D is such that the phase difference between the first signal light XIp and the third signal light XQp is 90 degrees, and the phase difference between the second signal light XIn and the fourth signal light XQn is 90 degrees. Furthermore, the relationship of the output light is such that the phase difference between the first signal light XIp and the second signal light XIn is 180 degrees, and the phase difference between the third signal light XQp and the fourth signal light XQn is 180 degrees. That is, the phase difference between the signal light and the local light in the first signal light XIp is 0 degrees, the phase difference between the signal light and the local light in the third signal light XQp is 90 degrees, the phase difference between the signal light and the local light in the second signal light XIn is 180 degrees, and the phase difference between the signal light and the local light in the fourth signal light XQn is 270 degrees.

[0016] The second optical hybrid circuit 236B causes the local light to interfere with the Y-polarized component signal light to obtain I-component and Q-component signal light. The second optical hybrid circuit 236B outputs the I-component optical signal of the Y-polarized component signal light to the fifth PD 237E and the sixth PD 237F. The second optical hybrid circuit 236B outputs a fifth signal light obtained by multiplexing the 0-degree signal light and the 90-degree local light based on the 0-degree signal light and the 0-degree local light to the fifth PD 237E. The fifth signal light is a YIp component signal light in which the phase difference between the signal light and the local light is 0 degrees. The second optical hybrid circuit 236B outputs a sixth signal light obtained by multiplexing the 90-degree signal light and the 0-degree local light based on the 0-degree signal light and the 0-degree local light to the sixth PD 237F. The sixth signal light is a YIn component signal light having a phase difference of 180 degrees between the signal light and the local light.

[0017] The second optical hybrid circuit 236B outputs the Q component optical signal of the Y polarization component signal light to the seventh PD 237G and the eighth PD 237H. The second optical hybrid circuit 236B outputs the seventh signal light obtained by multiplexing the 90 degree signal light and the 90 degree local light based on the 90 degree signal light and the 0 degree local light to the seventh PD 237G. The seventh signal light is a YQp component signal light in which the phase difference between the signal light and the local light is 90 degrees. The second optical hybrid circuit 236B outputs the eighth signal light obtained by multiplexing the 180 degree signal light and the 0 degree local light based on the 90 degree signal light and the 0 degree local light to the eighth PD 237H. The eighth signal light is a YQn component signal light in which the phase difference between the signal light and the local light is 270 degrees.

[0018] The fifth PD 237E electrically converts and gain-adjusts the fifth signal light YIp of the I-component of the Y-polarized component from the second optical hybrid circuit 236B, and outputs the gain-adjusted electrical signal to the fifth output port 238E. The sixth PD 237F electrically converts and gain-adjusts the sixth signal light YIn of the I-component of the Y-polarized component from the second optical hybrid circuit 236B, and outputs the gain-adjusted electrical signal to the sixth output port 238F.

[0019] The seventh PD 237G electrically converts and gain-adjusts the seventh signal light YQp of the Q component of the Y polarization component from the second optical hybrid circuit 236B, and outputs the gain-adjusted electrical signal to the seventh output port 238G. The eighth PD 237H electrically converts and gain-adjusts the eighth signal light YQn of the Q component of the Y polarization component from the second optical hybrid circuit 236B, and outputs the gain-adjusted electrical signal to the eighth output port 238H.

[0020] The relationship of the output light output from the second optical hybrid circuit 236B to the fifth to eighth PDs 237E to 237H is such that the phase difference between the fifth signal light YIp and the seventh signal light YQp is 90 degrees, and the phase difference between the sixth signal light YIn and the eighth signal light YQn is 90 degrees. Furthermore, the relationship of the output light is such that the phase difference between the fifth signal light YIp and the sixth signal light YIn is 180 degrees, and the phase difference between the seventh signal light YQp and the eighth signal light YQn is 180 degrees. That is, the phase difference between the signal light and the local light in the fifth signal light YIp is 0 degrees, the phase difference between the signal light and the local light in the seventh signal light YQp is 90 degrees, the phase difference between the signal light and the local light in the sixth signal light YIn is 180 degrees, and the phase difference between the signal light and the local light in the eighth signal light YQn is 270 degrees.

[0021] In the conventional test system 200, the optical receivers 220 are cut out from a wafer, and each optical receiver 220 is placed on a stage. Furthermore, a first polarization controller 212A of the test device 210 is connected to a first optical port 221A at a side end of the optical receiver 220 by a first optical fiber F11. A second polarization controller 212B of the test device 210 is connected to a second optical port 221B at a side end of the optical receiver 220 by a second optical fiber F12. Then, the test device 210 measures the electrical signals from the first to eighth output ports 238A to 238H, and calculates a phase error of the signal light with respect to 90 degrees based on the measurement result. The phase error is, for example, an error with respect to the original 90 degrees when the phase difference between the first signal light XIp and the third signal light XQp is originally 90 degrees.

[0022] However, in the conventional test system 200, it is necessary to perform alignment work for aligning the optical axis between the first optical port 221A and the first optical fiber F11, and the optical axis between the second optical port 221B and the second optical fiber F12, for each optical receiver 220. As a result, the workload for optically connecting the optical receiver 220 and the test device 210 to obtain the phase error becomes large.

[0023] Therefore, it is considered that the work efficiency can be improved if the optical receiver 220 can be tested in the wafer state before being made into a chip, but when testing in the wafer state, it is necessary to input light from the wafer surface direction using an optical fiber. Here, a test system 200A that adopts such a test method will be described.

[0024] Fig. 10 is an explanatory diagram showing an example of a conventional test system 200A. The test system 200A includes a wafer, such as silicon, on which a plurality of optical receivers 220 are formed, a test apparatus 210, a first optical fiber F11, and a second optical fiber F12. Note that the same components as those in the test apparatus 210 shown in Fig. 9 are denoted by the same reference numerals, and descriptions of the overlapping components and operations will be omitted.

[0025] A plurality of optical receivers 220 are formed on the wafer in a lattice arrangement. The optical receiver 220 has an optical circuit region 220A, a test circuit region 220B, and a dicing line DL that allows cutting between the optical circuit region 220A and the test circuit region 220B.

[0026] The optical circuit region 220A has a first optical port 221A and a first optical waveguide 223A that optically couples the first optical port 221A and the PBS 231 in the optical circuit 222. The optical circuit chip region A has a second optical port 221B and a second optical waveguide 223B that optically couples the second optical port 221B and the 1×2 coupler 235 in the optical circuit 222. The first optical port 221A is exposed at a side end of the optical circuit region 220A by forming the wafer into chips.

[0027] The test circuit area 220B has a first GC (Grating Coupler) 241A, a third optical waveguide 242A connected to the first GC 241A, a second GC 241B, and a fourth optical waveguide 242B connected to the second GC 241B. The first GC 241A is disposed on the surface of the test circuit area 220B, and is detachably connected to the first optical fiber F11 and is also connected to the third optical waveguide 242A. The third optical waveguide 242A is optically connected to the first optical port 221A in the optical circuit area 220A. The second GC 241B is disposed on the surface of the test circuit area 220B, and is detachably connected to the second optical fiber F12 and is also connected to the fourth optical waveguide 242B. The fourth optical waveguide 242B is optically connected to the second optical port 221B in the optical circuit area 220A.

[0028] In the test system 200A, the first optical fiber F11 is brought close to the first GC 241A from the wafer surface direction to input the signal light, and the signal light is input to the optical circuit 222. Furthermore, in the test system 200A, the second optical fiber F12 is brought close to the second GC 241B from the wafer surface direction to input the local light, and the local light is input to the optical circuit 222. As a result, testing in the wafer state is possible. The test device 210 measures the electrical signals from the first to eighth output ports 238A to 238H in response to the test light, and can obtain the phase error of the signal light with respect to 90 degrees based on the measurement results. [Prior art documents] [Patent documents]

[0029] [Patent Document 1] Japanese Patent Application Publication No. 5-333297 [Patent Document 2] JP 2020-30356 A [Patent Document 3] US Patent Application Publication No. 2021 / 0356517 [Patent Document 4] US Patent Application Publication No. 2019 / 0113415 Summary of the Invention [Problem to be solved by the invention]

[0030] The phase difference between the signal light and the local light of the first optical hybrid circuit 236A is determined by the optical length of the optical waveguide from the second light source 211B to the first optical hybrid circuit 236A and the optical length of the optical waveguide from the first light source 211A to the first optical hybrid circuit 236A. The phase difference between the signal light and the local light of the second optical hybrid circuit 236B is determined by the optical length of the optical waveguide from the second light source 211B to the second optical hybrid circuit 236B and the optical length of the optical waveguide from the first light source 211A to the second optical hybrid circuit 236B. Therefore, the test device 210 measures the phase difference of each output light from the output results of the first to eighth PDs 237A to 237H according to the fixed phase difference determined by the optical length. However, in order to obtain a highly accurate phase error, it is necessary to adjust the phase difference between the signal light and the local light and obtain a phase error corresponding to each phase difference when the phase difference between the signal light and the local light is from 0 degrees to 360 degrees.

[0031] In one aspect, an object of the present invention is to provide an optical receiver etc. that can obtain a phase error corresponding to each phase difference between a signal light and a local light beam when the phase difference between the signal light and the local light beam is from 0 degrees to 360 degrees while adjusting the phase difference between the signal light and the local light beam. [Means for solving the problem]

[0032] An optical receiver according to one embodiment includes an optical circuit having a first port for inputting a signal light and a second port for inputting a local light, and an optical hybrid circuit for outputting output light differing by 90 degrees based on the signal light and the local light. The optical receiver includes a phase adjustment unit that is arranged in a first optical waveguide that guides the signal light between the optical hybrid circuit and the first port, or in a second optical waveguide that guides the local light between the optical hybrid circuit and the second port, and that adjusts the phase of the guided light. Effect of the Invention

[0033] According to one aspect, while adjusting the phase difference between the signal light and the local light, a phase error corresponding to each phase difference between the signal light and the local light ranging from 0 degrees to 360 degrees can be obtained. [Brief description of the drawings]

[0034] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of a test system according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram showing an example of each output light for each phase difference of the optical hybrid circuit. [Diagram 3] FIG. 3 is an explanatory diagram illustrating an example of a test system according to the second embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating an example of a test system according to a third embodiment. [Diagram 5] FIG. 5 is an explanatory diagram illustrating an example of a test system according to a fourth embodiment. [Figure 6] FIG. 6 is an explanatory diagram showing an example of a schematic cross-sectional portion taken along line AA shown in FIG. [Figure 7] FIG. 7 is an explanatory diagram illustrating an example of a test system according to a fifth embodiment. [Figure 8] FIG. 8 is an explanatory diagram illustrating an example of an optical transceiver according to this embodiment. [Figure 9] FIG. 9 is an explanatory diagram showing an example of a conventional test system. [Figure 10] FIG. 10 is an explanatory diagram showing an example of a conventional test system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Hereinafter, the embodiments of the optical receiver and the like disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. In addition, the following examples may be appropriately combined as long as no contradiction occurs. EXAMPLES

[0036] Fig. 1 is an explanatory diagram showing an example of a test system 1 of Example 1. The test system 1 shown in Fig. 1 includes a test device 2, a wafer such as silicon on which a plurality of optical receivers 3 are formed, a first optical fiber F1, and a second optical fiber F2. The test device 2 includes a first light source 11A, a first polarization controller 12A, a second light source 11B, and a second polarization controller 12B.

[0037] The first light source 11A is, for example, a light source that emits a test light corresponding to the signal light. The first polarization controller 12A polarizes the test light corresponding to the signal light from the first light source 11A and outputs the polarized test light to the first optical fiber F1. The first polarization controller 12A controls the polarization of the test light to generate test light of the signal light of TE polarization and TM polarization.

[0038] The second light source 11B is, for example, a light source that emits test light corresponding to the local light. The second polarization controller 12B polarizes the test light corresponding to the local light from the second light source 11B and outputs the polarized test light to the second optical fiber F2. The second polarization controller 12B controls the polarization of the test light to generate the test light of the local light of TE polarization.

[0039] A plurality of optical receivers 3 are formed on the wafer in a lattice arrangement. The optical receiver 3 has an optical circuit area 3A, a test circuit area 3B, and a dicing line DL that can be cut between the optical circuit area 3A and the test circuit area 3B.

[0040] The optical circuit region 3A is, for example, an optical IC chip such as a digital coherent optical transceiver. The optical circuit region 3A is an optical chip cut out from a wafer. The optical circuit region 3A has a first optical port 21A, a second optical port 21B, an optical circuit 22, a first optical waveguide 23A, a second optical waveguide 23B, an electrode wiring 24, and an electrode pad 25. The first optical port 21A is an optical port that is exposed to a chip end surface D1, which is a side end surface of the optical circuit region 3A, by forming the wafer into a chip, and is optically connected to the first optical fiber F1 to input a signal light from the first optical fiber F1. The second optical port 21B is an optical port that is exposed to a chip end surface D1 of the optical circuit region 3A by forming the wafer into a chip, and is optically connected to the second optical fiber F2 to input a local light from the second optical fiber F2. The first optical waveguide 23A is an optical waveguide such as a Si waveguide through which the signal light is guided between the first optical port 21A and the optical circuit 22. The second optical waveguide 23B is an optical waveguide such as a Si waveguide through which the signal light is guided between the second optical port 21B and the optical circuit 22. The optical circuit 22 is a circuit such as an optical receiver. The electrode wiring 24 is an electric wiring that applies a voltage to a part of the optical circuit 22. The electrode pad 25 is a pad that is electrically connected to the electrode wiring 24 and applies a voltage to the electrode wiring 24.

[0041] The optical circuit 22 has a PBS (Polarization Beam Splitter) 31 connected to the first optical waveguide 23A, a PR (Polarization Rotator) 32, a first monitor PD (Photo Detector) 33A, and a first VOA (Variable Optical Attenuator) 34A. The optical circuit 22 has a second monitor PD 33B, a second VOA 34B, a 1×2 coupler 35, a first optical hybrid circuit 36A, and a second optical hybrid circuit 36B. The optical circuit 22 has first to fourth PDs 37A to 37D, first to fourth output ports 38A to 38D, fifth to eighth PDs 37E to 37H, and fifth to eighth output ports 38E to 38H.

[0042] The first optical port 21A is formed on the chip end face D1 of the optical circuit region 3A and is, for example, an edge coupler of a port that connects to a first optical fiber F1 that inputs a signal light. The second optical port 21B is formed on the chip end face D1 in the optical circuit region 3A and is, for example, an edge coupler of a port that connects to a second optical fiber F2 that inputs a local light.

[0043] The PBS 31 separates the signal light input from the first optical port 21A into two orthogonal polarization states, for example, an X-polarized component which is TE (Transverse Electric) polarized wave and a Y-polarized component which is TM (Transverse Magnetic) polarized wave. The PBS 31 outputs the X-polarized component signal light to the first optical hybrid circuit 36A. Furthermore, the PR 32 rotates the Y-polarized component signal light from the PBS 31 by 90 degrees, converts it into a Y-polarized component signal light after polarization rotation, and outputs it to the second optical hybrid circuit 36B. The 1×2 coupler 35 optically branches the local light input from the second optical port 21B, and outputs the TE-polarized local light to the first optical hybrid circuit 36A and the second optical hybrid circuit 36B.

[0044] The first monitor PD33A is electrically connected to the electrode wiring 24, and detects the power of the signal light guided through the optical waveguide between the PBS 31 and the first optical hybrid circuit 36A in response to a voltage applied to the electrode wiring 24. The first VOA34A is electrically connected to the electrode wiring 24, and adjusts the power of the signal light guided through the optical waveguide between the PBS 31 and the first optical hybrid circuit 36A in response to a voltage applied to the electrode wiring 24.

[0045] The second monitor PD33B is electrically connected to the electrode wiring 24, and detects the power of the signal light guided through the optical waveguide between the PR32 and the second optical hybrid circuit 36B in response to the voltage applied to the electrode wiring 24. The second VOA34B is electrically connected to the electrode wiring 24, and adjusts the power of the signal light guided through the optical waveguide between the PR32 and the second optical hybrid circuit 36B in response to the voltage applied to the electrode wiring 24.

[0046] The first optical hybrid circuit 36A causes the local light to interfere with the signal light of the X-polarized component to obtain the optical signals of the I component and the Q component. The I component is an in-phase axis component, and the Q component is an orthogonal axis component. The first optical hybrid circuit 36A outputs the optical signal of the I component of the signal light of the X-polarized component to the first PD 37A and the second PD 37B. The first optical hybrid circuit 36A outputs the first signal light obtained by multiplexing the 0-degree signal light and the 90-degree local light based on the 0-degree signal light and the 0-degree local light to the first PD 37A. The first signal light is a signal light of the XIp component in which the phase difference between the signal light and the local light is 0 degrees. The first optical hybrid circuit 36A outputs the second signal light obtained by multiplexing the 90-degree signal light and the 0-degree local light based on the 0-degree signal light and the 0-degree local light to the second PD 37B. The second signal light is an XIn component signal light having a phase difference of 180 degrees between the signal light and the local light.

[0047] The first optical hybrid circuit 36A outputs the Q component optical signal of the X polarization component signal light to the third PD 37C and the fourth PD 37D. The first optical hybrid circuit 36A outputs the third signal light obtained by multiplexing the 90 degree signal light and the 90 degree local light based on the 90 degree signal light and the 0 degree local light to the third PD 37C. The third signal light is an XQp component signal light in which the phase difference between the signal light and the local light is 90 degrees. The first optical hybrid circuit 36A outputs the fourth signal light obtained by multiplexing the 180 degree signal light and the 0 degree local light based on the 90 degree signal light and the 0 degree local light to the fourth PD 37D. The fourth signal light is an XQn component signal light in which the phase difference between the signal light and the local light is 270 degrees.

[0048] The first PD 37A electrically converts and gain-adjusts the first signal light XIp of the I component of the X polarization component from the first optical hybrid circuit 36A, and outputs the gain-adjusted electrical signal to the first output port 38A. The second PD 37B electrically converts and gain-adjusts the second signal light XIn of the I component of the X polarization component from the first optical hybrid circuit 36A, and outputs the gain-adjusted electrical signal to the second output port 38B.

[0049] The third PD 37C electrically converts and gain-adjusts the third signal light XQp of the Q component of the X polarization component from the first optical hybrid circuit 36A, and outputs the gain-adjusted electrical signal to the third output port 38C. The fourth PD 37D electrically converts and gain-adjusts the fourth signal light XQn of the Q component of the X polarization component from the first optical hybrid circuit 36A, and outputs the gain-adjusted electrical signal to the fourth output port 38D.

[0050] The second optical hybrid circuit 36B causes the local light to interfere with the Y-polarized signal light to obtain I- and Q-component optical signals. The second optical hybrid circuit 36B outputs the I-component optical signal of the Y-polarized signal light to the fifth PD 37E and the sixth PD 37F. The second optical hybrid circuit 36B outputs a fifth signal light obtained by multiplexing the 0-degree signal light and the 90-degree local light based on the 0-degree signal light and the 0-degree local light to the fifth PD 37E. The fifth signal light is a YIp component signal light in which the phase difference between the signal light and the local light is 0 degrees. The second optical hybrid circuit 36B outputs a sixth signal light obtained by multiplexing the 90-degree signal light and the 0-degree local light based on the 0-degree signal light and the 0-degree local light to the sixth PD 37F. The sixth signal light is a YIn component signal light in which the phase difference between the signal light and the local light is 180 degrees.

[0051] The second optical hybrid circuit 36B outputs the Q component optical signal of the Y polarization component signal light to the seventh PD 37G and the eighth PD 37H. The second optical hybrid circuit 36B outputs the seventh signal light obtained by multiplexing the 90 degree signal light and the 90 degree local light based on the 90 degree signal light and the 0 degree local light to the seventh PD 37G. The seventh signal light is a YQp component signal light in which the phase difference between the signal light and the local light is 90 degrees. The second optical hybrid circuit 36B outputs the eighth signal light obtained by multiplexing the 180 degree signal light and the 0 degree local light based on the 90 degree signal light and the 0 degree local light to the eighth PD 37H. The eighth signal light is a YQn component signal light in which the phase difference between the signal light and the local light is 270 degrees.

[0052] The fifth PD 37E electrically converts and gain-adjusts the fifth signal light YIp of the I-component of the Y-polarized component from the second optical hybrid circuit 36B, and outputs the gain-adjusted electrical signal to the fifth output port 38E. The sixth PD 37F electrically converts and gain-adjusts the sixth signal light YIn of the I-component of the Y-polarized component from the second optical hybrid circuit 36B, and outputs the gain-adjusted electrical signal to the sixth output port 38F.

[0053] The seventh PD 37G electrically converts and gain-adjusts the seventh signal light YQp of the Q component of the Y polarization component from the second optical hybrid circuit 36B, and outputs the gain-adjusted electrical signal to the seventh output port 38G. The eighth PD 37H electrically converts and gain-adjusts the eighth signal light YQn of the Q component of the Y polarization component from the second optical hybrid circuit 36B, and outputs the gain-adjusted electrical signal to the eighth output port 38H.

[0054] The test circuit area 3B has a first GC (Grating Coupler) 41A, a third optical waveguide 42A connected to the first GC 41A, a second GC 41B, and a fourth optical waveguide 42B connected to the second GC 41B. The test circuit area 3B has a PS (Phase Shifter) 43, an electrode wiring 44, and an electrode pad 45. The first GC 41A is disposed on the surface of the test circuit area 3B, and is detachably connected to the first optical fiber F1 and is connected to the third optical waveguide 42A. The third optical waveguide 42A is optically connected to the first optical port 21A in the optical circuit area 3A. The second GC 41B is disposed on the surface of the test circuit area 3B, and is detachably connected to the second optical fiber F2 and is connected to the fourth optical waveguide 42B. The fourth optical waveguide 42B is optically connected to the second optical port 21B in the optical circuit region 3A.

[0055] The PS43 is a phase adjustment unit disposed in the fourth optical waveguide 42B between the second GC 41B and the second optical waveguide 23B in the optical circuit region 3A, and adjusts the phase angle of the local light guided in the fourth optical waveguide 42B. The PS43 adjusts the phase angle of the local light guided by the fourth optical waveguide 42B using the electro-optic effect or the thermo-optic effect. The electrode wiring 44 is an electric wiring that is electrically connected to the PS43 and applies a voltage to the PS43. The electrode pad 45 is a pad that is electrically connected to the electrode wiring 44 and applies a voltage to the electrode wiring 44.

[0056] The PS 43 adjusts the phase angle of the local light guided through the fourth optical waveguide 42B, thereby adjusting the phase angle of the local light input to the first optical hybrid circuit 36A and the second optical hybrid circuit 36B. As a result, the phase difference between the signal light and the local light of the first optical hybrid circuit 36A and the second optical hybrid circuit 36B can be freely adjusted.

[0057] The relationship of the output light output from the first optical hybrid circuit 36A to the first to fourth PDs 37A to 37D is such that the phase difference between the first signal light XIp and the third signal light XQp is 90 degrees, and the phase difference between the second signal light XIn and the fourth signal light XQn is 90 degrees. Furthermore, the relationship of the output light is such that the phase difference between the first signal light XIp and the second signal light XIn is 180 degrees, and the phase difference between the third signal light XQp and the fourth signal light XQn is 180 degrees. In the first signal light XIp, the phase difference between the signal light and the local light is 0 degrees, in the third signal light XQp, the phase difference between the signal light and the local light is 90 degrees, in the second signal light XIn, the phase difference between the signal light and the local light is 180 degrees, and in the fourth signal light XQn, the phase difference between the signal light and the local light is 270 degrees.

[0058] The relationship of the output light output from the second optical hybrid circuit 36B to the fifth PD to the eighth PD 37E to 37H is such that the phase difference between the fifth signal light YIp and the seventh signal light YQp is 90 degrees, and the phase difference between the sixth signal light YIn and the eighth signal light YQn is 90 degrees. Furthermore, the relationship of the output light is such that the phase difference between the fifth signal light YIp and the sixth signal light YIn is 180 degrees, and the phase difference between the seventh signal light YQp and the eighth signal light YQn is 180 degrees. In the fifth signal light YIp, the phase difference between the signal light and the local light is 0 degrees, in the seventh signal light YQp, the phase difference between the signal light and the local light is 90 degrees, in the sixth signal light YIn, the phase difference between the signal light and the local light is 180 degrees, and in the eighth signal light YQn, the phase difference between the signal light and the local light is 270 degrees.

[0059] FIG. 2 is an explanatory diagram showing an example of each output light for each phase difference of the optical hybrid circuit. The optical hybrid circuit is the first optical hybrid circuit 36A or the second optical hybrid circuit 36B. When the phase difference between the signal light and the local light is 0 degrees, the optical hybrid circuit outputs the output light Ip, the output light In, the output light Qp, and the output light Qn. When the optical hybrid circuit is the first optical hybrid circuit 36A, the output light Ip corresponds to the first signal light XIp, the output light In corresponds to the second signal light XIn, the output light Qp corresponds to the third signal light XQp, and the output light Qn corresponds to the fourth signal light XQn. When the optical hybrid circuit is the second optical hybrid circuit 36B, the output light Ip corresponds to the fifth signal light YIp, the output light In corresponds to the sixth signal light YIn, the output light Qp corresponds to the seventh signal light YQp, and the output light Qn corresponds to the eighth signal light YQn.

[0060] The optical hybrid circuit outputs output light Ip, output light In, output light Qp, and output light Qn when the phase difference between the signal light and the local light is 90 degrees. The optical hybrid circuit outputs output light Ip, output light In, output light Qp, and output light Qn when the phase difference between the signal light and the local light is 180 degrees. The optical hybrid circuit 36 ​​outputs output light Ip, output light In, output light Qp, and output light Qn when the phase difference between the signal light and the local light is 270 degrees.

[0061] That is, the first optical hybrid circuit 36A can output first to fourth signal lights when the phase difference between the signal light and the local light is 0 degrees to 360 degrees by adjusting the phase angle of the local light in the PS 43. Similarly, the second optical hybrid circuit 36B can output fifth to eighth signal lights when the phase difference between the signal light and the local light is 0 degrees to 360 degrees by adjusting the phase angle of the local light in the PS 43.

[0062] The test device 2 obtains, as phase errors, the errors with respect to a phase difference of 90 degrees between the first signal light and the second signal light, between the second signal light and the third signal light, between the third signal light and the fourth signal light, and between the fourth signal light and the first signal light, which are output for each phase difference of the first optical hybrid circuit 36A.

[0063] The test device 2 obtains, as phase errors, the errors with respect to a phase difference of 90 degrees between the fifth signal light and the sixth signal light, between the sixth signal light and the seventh signal light, between the seventh signal light and the eighth signal light, and between the eighth signal light and the fifth signal light output for each phase difference of the second optical hybrid circuit 36B.

[0064] In other words, the PS 43 adjusts the phase angle of the local light guided through the fourth optical waveguide 42B to adjust the phase difference between the local light and the signal light input to the first optical hybrid circuit 36A and the second optical hybrid circuit 36B. As a result, the phase difference between the signal light and the local light of the first optical hybrid circuit 36A and the second optical hybrid circuit 36B can be freely adjusted.

[0065] In the test system 1 of the first embodiment, the phase difference between the signal light and the local light of the first optical hybrid circuit 36A (second optical hybrid circuit 36B) is freely adjusted within a range of 0 degrees to 360 degrees by adjusting the phase angle of the local light in the PS 43. As a result, a highly accurate phase error corresponding to each phase difference when the phase difference between the signal light and the local light is 0 degrees to 360 degrees is obtained, thereby improving the wafer test accuracy.

[0066] Although the case where the PS43 is arranged in the test circuit area 3B of the first embodiment has been illustrated, the present invention is not limited to this, and the PS43 may be arranged in the optical circuit area 3A instead of the test circuit area 3B, and can be modified as appropriate. Therefore, this embodiment will be described below as the second embodiment. EXAMPLES

[0067] 3 is an explanatory diagram showing an example of a test system 1A of Example 2. The same components as those in the test system 1 of Example 1 are given the same reference numerals, and explanations of the overlapping components and operations are omitted. The difference between the test system 1 of Example 1 and the test system 1A of Example 2 is that the PS 43A, electrode wiring 44A, and electrode pads 45A are arranged in the optical circuit area 3A instead of the test circuit area 3B.

[0068] The optical circuit region 3A has a PS43A, an electrode wiring 44A, and an electrode pad 45A. The PS43A is disposed in the second optical waveguide 23B between the second optical port 21B and the 1×2 coupler 35, and is a phase adjustment unit that adjusts the phase angle of the local light guided through the second optical waveguide 23B. The electrode wiring 44A is a wiring that is electrically connected to the PS43A and applies a voltage to the PS43A. The electrode pad 45A is a pad that is electrically connected to the electrode wiring 44A and applies a voltage to the electrode wiring 44A.

[0069] The PS43A adjusts the phase difference between the signal light and the local light of the first optical hybrid circuit 36A and the second optical hybrid circuit 36B by adjusting the phase angle of the local light guided through the second optical waveguide 23B. As a result, the phase difference of the first optical hybrid circuit 36A and the second optical hybrid circuit 36B can be freely set within the range of 0 degrees to 360 degrees. As a result, a highly accurate phase error corresponding to each phase difference when the phase difference between the signal light and the local light is 0 degrees to 360 degrees is obtained, thereby improving the accuracy of the wafer test.

[0070] In the test system 1A of the second embodiment, when the optical loss due to the PS 43A is small, the PS 43A, the electrode wiring 44A, and the electrode pad 45A can be disposed within the optical circuit region 3A.

[0071] Although the example of applying a voltage from the electrode pad 45 in the test circuit region 3B to the PS 43 through the electrode wiring 44 in the first embodiment has been described, the present invention is not limited to this and can be modified as appropriate. Therefore, the embodiment will be described below as a third embodiment. EXAMPLES

[0072] 4 is an explanatory diagram showing an example of a test system 1B of Example 3. The same components as those in the test system 1 of Example 1 are given the same reference numerals, and explanations of the overlapping components and operations are omitted. The difference between the test system 1 of Example 1 and the test system 1B of Example 3 is that the electrode pad for the voltage applied to the PS43 is shared by the electrode pad 25 in the optical circuit area 3A.

[0073] The test circuit area 3B has a PS43 and an electrode wiring 44B. The PS43 is disposed in the fourth optical waveguide 42B between the second GC 41B and the second optical waveguide 23B in the optical circuit area 3A, and is a phase adjustment unit that adjusts the phase angle of the local light guided through the fourth optical waveguide 42B. The electrode wiring 44B is electrically connected to the PS43 and is a wiring that applies a voltage to the PS43.

[0074] The optical circuit region 3A has an electrode wiring 24A that electrically connects between the electrode wiring 44B and the electrode wiring 24. An electrode pad 25 connected to the electrode wiring 24 applies a voltage to the electrode wiring 44B connected to the electrode wiring 24A. The electrode wiring 24A is cut after the wafer is diced and cut into the optical circuit region 3A after testing, so that it does not affect the operation of the first monitor PD33A, the second monitor PD33B, the first VOA 34A, and the second VOA 34B during actual operation.

[0075] The PS43 adjusts the phase difference between the local light and the signal light input to the first optical hybrid circuit 36A and the second optical hybrid circuit 36B by adjusting the phase angle of the local light guided through the second optical waveguide 23B. As a result, the phase difference between the signal light and the local light of the first optical hybrid circuit 36A and the second optical hybrid circuit 36B can be freely adjusted within a range of 0 degrees to 360 degrees. A highly accurate phase error corresponding to each phase difference when the phase difference between the signal light and the local light is 0 degrees to 360 degrees is obtained, thereby improving the accuracy of the wafer test.

[0076] In the test system 1 of the first embodiment, an electrode pad 45 for applying a voltage to the PS43 is required, and an area for arranging the electrode pad 45 is required. In addition, a probe for passing a current through the electrode pad 45 during testing is separately required. In the test system 1B of the third embodiment, the electrode wirings 24 of the first monitor PD33A, the second monitor PD33B, the first VOA34A, and the second VOA34B provided in the optical circuit region 3A are connected to the PS43, so that the electrode pad 25 in the optical circuit region 3A can be shared.

[0077] In the test system 1B of Example 3, the electrode pad of the PS43 is shared by the electrode pad 25 in the optical circuit area 3A, and the electrode wiring 44B and the electrode wiring 24A are electrically connected directly to each other. However, when dicing between the electrode wiring 44B in the test circuit area 3B and the electrode wiring 24A in the optical circuit area 3A, the electrode wiring may also be cut, causing contamination of the electrode material, which may result in contamination of the optical circuit area 3A or the dicer. Therefore, this embodiment will be described below as Example 4. EXAMPLES

[0078] 5 is an explanatory diagram showing an example of a test system 1C of Example 4. The same components as those of the test system 1B of Example 3 are given the same reference numerals, and the description of the overlapping components and operations is omitted. The test system 1B of Example 3 differs from the test system 1C of Example 4 in that the electrode wiring 44B in the test circuit area 3B, which is electrically connected to the PS43, and the electrode wiring 24A in the optical circuit area 3A are connected by a via 46. The via 46 has a first via 46A arranged on the test circuit area 3B side and a second via 46B arranged on the optical circuit area 3A side.

[0079] Fig. 6 is an explanatory diagram showing an example of a schematic cross-sectional portion taken along line AA shown in Fig. 5. The schematic cross-sectional portion taken along line AA shown in Fig. 6 is a connection portion that connects electrode wiring 44B and electrode wiring 24A. The connection portion is made of a Si substrate 51 and a SiO 2 etc., and electrode wiring 44B and electrode wiring 24A covered with cladding 52. Furthermore, the joining portion has a first via 46A and a second via 46B covered with cladding 52, and a Si-doped electrode wiring 47 of a doped semiconductor material covered with cladding 52.

[0080] The first via 46A is electrically connected to the electrode wiring 44B in the test circuit region 3B, and is also electrically connected to the Si-doped electrode wiring 47 on the test circuit region 3B side. The second via 46B is electrically connected to the electrode wiring 24A in the optical circuit region 3A, and is also electrically connected to the Si-doped electrode wiring 47 on the optical circuit region 3A side. In other words, since the Si-doped electrode wiring 47 is disposed in the same layer as the second optical waveguide 23B, the Si-doped electrode wiring 47 can be formed without significantly changing the manufacturing process.

[0081] In the test system 1C of the fourth embodiment, the electrode wiring 44B in the test circuit region 3B and the electrode wiring 24A in the optical circuit region 3A are electrically connected through the vias 46 and the Si-doped electrode wiring 47. As a result, the electrode wiring that is cut when dicing between the electrode wiring 44B in the test circuit region 3B and the electrode wiring 24A in the optical circuit region 3A is the Si-doped electrode wiring 47, so that the influence of contamination of the electrode material can be reduced.

[0082] Although the example shows that PS43 is placed in the test circuit area 3B or the optical circuit area 3A, it may also be placed between the second polarization controller 12B and the second optical fiber F2 in the test equipment 2, and this can be changed as appropriate.

[0083] The first optical waveguide 23A, the second optical waveguide 23B, the third optical waveguide 42A and the fourth optical waveguide 42B may be, for example, a channel waveguide, a rib waveguide, a ridge waveguide, a slab waveguide or the like and can be appropriately changed.

[0084] In addition, although the PS43 is arranged at the position of the optical waveguide that guides the local light to adjust the phase angle of the local light in the above embodiment, it may be arranged at the position of the optical waveguide that guides the signal light. Therefore, this embodiment will be described below as Example 5. EXAMPLES

[0085] 7 is an explanatory diagram showing an example of a test system 1D of Example 5. The same components as those in the test system 1 of Example 1 are denoted by the same reference numerals, and explanations of the overlapping components and operations will be omitted. The difference between the test system 1 of Example 1 and the test system 1D of Example 5 is that the PS43C is arranged at the position of the optical waveguide that guides the signal light, instead of being arranged at the position of the optical waveguide that guides the local light.

[0086] The PS43C is a phase adjustment unit disposed in the third optical waveguide 42A between the first GC 41A and the first optical waveguide 23A in the optical circuit region 3A, and adjusts the phase angle of the signal light guided through the third optical waveguide 42A. The PS43C adjusts the phase angle of the guided signal light using the electro-optic effect or the thermo-optic effect. The electrode wiring 44C is an electric wiring that is electrically connected to the PS43C and applies a voltage to the PS43C. The electrode pad 45C is a pad that is electrically connected to the electrode wiring 44C and applies a voltage to the electrode wiring 44C.

[0087] The PS43C adjusts the phase angle of the signal light guided through the third optical waveguide 42A, thereby adjusting the phase angle of the signal light input to the first optical hybrid circuit 36A and the second optical hybrid circuit 36B. As a result, the phase difference between the signal light and the local light of the first optical hybrid circuit 36A and the second optical hybrid circuit 36B can be freely adjusted.

[0088] The first optical hybrid circuit 36A can adjust the phase angle of the signal light with the PS43C and output first to fourth signal lights when the phase difference between the signal light and the local light is 0 degrees to 360 degrees. Similarly, the second optical hybrid circuit 36B can adjust the phase angle of the signal light with the PS43C and output fifth to eighth signal lights when the phase difference between the signal light and the local light is 0 degrees to 360 degrees.

[0089] The test device 2 obtains, as phase errors, the errors with respect to a phase difference of 90 degrees between the first signal light and the second signal light, between the second signal light and the third signal light, between the third signal light and the fourth signal light, and between the fourth signal light and the first signal light, which are output for each phase difference of the first optical hybrid circuit 36A.

[0090] The test device 2 obtains, as phase errors, the errors with respect to a phase difference of 90 degrees between the fifth signal light and the sixth signal light, between the sixth signal light and the seventh signal light, between the seventh signal light and the eighth signal light, and between the eighth signal light and the fifth signal light output for each phase difference of the second optical hybrid circuit 36B.

[0091] In other words, the PS43C adjusts the phase difference between the local light and the signal light input to the first optical hybrid circuit 36A and the second optical hybrid circuit 36B by adjusting the phase angle of the signal light guided through the third optical waveguide 42A. As a result, the phase difference between the signal light and the local light of the first optical hybrid circuit 36A and the second optical hybrid circuit 36B can be freely adjusted.

[0092] In the test system 1D of the fifth embodiment, the phase angle of the signal light is adjusted by the PS43C to freely adjust the phase difference between the signal light and the local light of the first optical hybrid circuit 36A (second optical hybrid circuit 36B) within the range of 0 degrees to 360 degrees. As a result, a highly accurate phase error corresponding to each phase difference when the phase difference between the signal light and the local light is 0 degrees to 360 degrees is obtained, thereby improving the wafer test accuracy.

[0093] FIG. 8 is an explanatory diagram showing an example of an optical transceiver 70 according to the present embodiment. The optical transceiver 70 shown in FIG. 8 is connected to an output optical fiber and an input optical fiber. The optical transceiver 70 includes a light source 71, a DSP (Digital Signal Processor) 72, and an optical transceiver 73. The optical transceiver 73 includes an optical transmitter 73A and an optical receiver 73B. The DSP 72 is an electrical component that performs digital signal processing. For example, the DSP 72 performs processing such as encoding transmission data, generates an electrical signal including the transmission data, and outputs the generated electrical signal to the optical transmitter 73A. The DSP 72 also obtains an electrical signal including reception data from the optical receiver 73B, and obtains reception data by performing processing such as decoding the obtained electrical signal.

[0094] The light source 71 includes, for example, a laser diode, and generates light of a predetermined wavelength and supplies it to the optical transmitter 73A and the optical receiver 73B. The optical transmitter 73A modulates the light supplied from the light source 71 with an electrical signal output from the DSP 72, and outputs the obtained transmission light to an optical fiber. The optical transmitter 73A includes an optical modulator element 73A1 that generates transmission light by modulating the light supplied from the light source 71 with an electrical signal input to the optical modulator when the light propagates through the waveguide.

[0095] The optical receiver 73B has an optical receiver element 73B1 that receives an optical signal from an optical fiber and demodulates the received light using light supplied from the light source 71. The optical receiver 73B then converts the demodulated received light into an electrical signal and outputs the converted electrical signal to the DSP 72. The optical receiver 73B incorporates an optical receiver that is a planar optical waveguide element that guides light.

[0096] The optical receiver in the optical transceiver 70 has a first port for inputting a signal light, a second port for inputting a local light, and an optical circuit including an optical hybrid circuit for outputting output light differing by 90 degrees based on the signal light and the local light. The optical receiver has a phase adjustment unit arranged in a first optical waveguide for guiding the signal light between the optical hybrid circuit and the first port, or in a second optical waveguide for guiding the local light between the optical hybrid circuit and the second port, for adjusting the phase of the guided light. As a result, while adjusting the phase difference between the signal light and the local light, it is possible to obtain a phase error corresponding to each phase difference between the signal light and the local light from 0 degrees to 360 degrees.

[0097] For convenience of explanation, the optical transceiver 70 has been illustrated as having the optical transmitter 73A and the optical receiver 73B built in, but the optical transceiver 70 may have either the optical transmitter 73A or the optical receiver 73B built in. For example, an optical receiver may be applied to the optical transceiver 70 having the optical receiver 73B built in, and modifications can be made as appropriate.

[0098] Furthermore, each component of each unit shown in the figure does not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each unit is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0099] Furthermore, the various processing functions performed by each device may be executed in whole or in part on a CPU (Central Processing Unit) (or a microcomputer such as an MPU (Micro Processing Unit) or an MCU (Micro Controller Unit)). It goes without saying that the various processing functions may be executed in whole or in part on a program analyzed and executed by a CPU (or a microcomputer such as an MPU or an MCU), or on hardware using wired logic. [Explanation of symbols]

[0100] 3 Optical Receiver 21A First Optical Port 21B Second Optical Port 23A First Optical Waveguide 23B Second optical waveguide 36A First Optical Hybrid Circuit 36B Second optical hybrid circuit 43 PS 70 Optical Transceiver 72 DSP 73 Optical Transmitter / Receiver 73A1 Optical modulator element 73B Optical Receiver 73B1 Optical receiver element

Claims

1. a first port for inputting a signal light and a second port for inputting a local light; an optical circuit including an optical hybrid circuit that outputs output light differing by 90 degrees based on the signal light and the local light, an optical receiver comprising: a phase adjustment unit that is arranged in a first optical waveguide that guides the signal light between the optical hybrid circuit and the first port, or in a second optical waveguide that guides the local light between the optical hybrid circuit and the second port, and that adjusts the phase of the guided light.

2. The phase adjustment unit is 2. The optical receiver according to claim 1, wherein the phase angle of the local light or the signal light is adjusted to adjust the output light of the optical hybrid circuit.

3. a test circuit area having the first port and the second port; an optical circuit region including the optical circuit; 2. The optical receiver according to claim 1, further comprising a dicing line that enables cutting between the test circuit region and the optical circuit region.

4. The phase adjustment unit is 4. The optical receiver according to claim 3, which is disposed in the test circuit area.

5. The phase adjustment unit is 4. The optical receiver according to claim 3, which is disposed in the optical circuit region.

6. The optical circuit region includes: a first electrode wiring electrically connected to the optical circuit; an electrode pad electrically connected to the first electrode wiring; A second electrode wiring electrically connected to the phase adjustment unit; a third electrode wiring that electrically connects the first electrode wiring and the second electrode wiring; 5. The optical receiver according to claim 4, further comprising:

7. The optical circuit region includes: a first electrode wiring electrically connected to the optical circuit; an electrode pad electrically connected to the first electrode wiring; The test circuit area includes: The phase adjustment unit; a second electrode wiring electrically connected to the phase adjustment unit; a third electrode wiring made of a doped semiconductor material electrically connecting between the first electrode wiring and the second electrode wiring at a portion crossing the dicing line; 5. The optical receiver according to claim 4, further comprising:

8. An optical receiver including an optical receiver element that converts a received signal light into an electrical signal, The optical receiver element comprises: a first port for inputting a signal light and a second port for inputting a local light; an optical circuit including an optical hybrid circuit that outputs output light differing by 90 degrees based on the signal light and the local light; a phase adjustment unit that is arranged in a first optical waveguide that guides the signal light between the optical hybrid circuit and the first port or in a second optical waveguide that guides the local light between the optical hybrid circuit and the second port, and adjusts the phase of the guided light; 1. An optical receiver comprising:

9. an optical modulator element that modulates guided light in response to an electrical signal; an optical receiver element that converts received light into an electrical signal; a signal processing unit that generates an electrical signal to the optical modulator element and acquires the electrical signal from the optical receiver element, The optical receiver element comprises: a first port for inputting a signal light and a second port for inputting a local light; an optical circuit including an optical hybrid circuit that outputs output light differing by 90 degrees based on the signal light and the local light; a phase adjustment unit that is arranged in a first optical waveguide that guides the signal light between the optical hybrid circuit and the first port or in a second optical waveguide that guides the local light between the optical hybrid circuit and the second port, and adjusts the phase of the guided light; 1. An optical transceiver comprising:

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