Optical device, optical transmitter, and optical receiver

Abstract

To provide an optical device capable of accurately evaluating polarization dependence of an optical circuit.SOLUTION: The optical device includes a region on which an optical circuit and a polarization rotation mechanism are mounted. The region has a first optical waveguide optically connected to the optical circuit. The region further includes a first edge coupler that is disposed in the vicinity of the boundary with a dicing line that allows the region to be separable, is connected to the first optical waveguide, and is connectable to one end of the polarization rotation mechanism across the dicing line.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical device, an optical transmitter, and an optical receiver. [Background technology]

[0002] 8 is an explanatory diagram showing an example of a conventional test system 100. The test system 100 includes a wafer made of, for example, silicon, on which a plurality of optical chips 101 are formed, a test device 140, and an optical fiber .

[0003] A plurality of optical chips 101 are formed on a wafer in a lattice-like arrangement. The optical chip 101 includes an optical circuit chip 110, a test circuit chip 120, and a dicing line DL along which the optical circuit chip 110 and the test circuit chip 120 can be cut. The optical circuit chip 110 includes an optical circuit 111, a first optical waveguide 112, and a first EC (Edge Coupler) 113. The optical circuit 111 is, for example, a circuit such as an optical transmitter or optical receiver in a digital coherent optical transceiver. The first optical waveguide 112 is a waveguide through which light is guided between the first EC 113 and the optical circuit 111. The first EC 113 is disposed near the end face of the optical circuit chip 110 on the dicing line DL side.

[0004] The test circuit chip 120 has a GC (Grating Coupler) 121, a second optical waveguide 122, and a second EC 123. The GC 121 is disposed on the surface of the test circuit chip 120, and is detachably connected to the optical fiber 130 and also connected to the second optical waveguide 122. The second optical waveguide 122 is a waveguide through which light is guided between the GC 121 and the second EC 123. The second EC 123 is disposed near the end face of the test circuit chip 120 on the dicing line DL side. The second EC 123 is optically coupled to the first EC 113 of the optical circuit chip 110, thereby optically connecting the second optical waveguide 122 in the test circuit chip 120 and the first optical waveguide 112 in the optical circuit chip 110.

[0005] The test equipment 140 includes a light source 141, a polarization controller 142, a circulator 143, and an optical power meter 144. The light source 141 is a light source that emits test light corresponding to, for example, received light, local light, or transmitted light. The polarization controller 142 polarizes the test light from the light source 141 and outputs the polarized test light to the circulator 143. The polarization controller 142 controls the polarization of the test light to generate TM light or TM test light. The circulator 143 outputs the test light input from the polarization controller 142 to the optical fiber 130 and outputs reflected return light of the test light input from the optical fiber 130 to the optical power meter 144. The optical power meter 144 receives reflected return light of the test light from the optical circuit 111 from the circulator 143 and measures the power of the reflected return light.

[0006] Next, the operation of the test system 100 will be described. The polarization controller 142 in the test device 140 polarizes the test light from the light source 141 and outputs the polarized test light to the circulator 143. The circulator 143 outputs the polarized test light to the optical fiber 130. The GC 121 on the test circuit chip 120 inputs the test light from the optical fiber 130 to the second optical waveguide 122. Furthermore, the optical circuit chip 110 inputs the test light from the first EC 113 connected to the second optical waveguide 122, and inputs the input test light to the first optical waveguide 112.

[0007] The first optical waveguide 112 inputs the test light to the optical circuit 111. The optical circuit 111 outputs reflected returning light of the test light to the first optical waveguide 112. The first optical waveguide 112 outputs the reflected returning light to the second optical waveguide 122 through the first EC 113. The second optical waveguide 122 outputs the reflected returning light from the first optical waveguide 112 to the optical fiber 130 via the GC 121. Furthermore, the circulator 143 outputs the reflected returning light from the optical fiber 130 to the optical power meter 144. The optical power meter 144 measures the power of the reflected returning light of the test light from the circulator 143.

[0008] In the test system 100, an optical fiber 130 is connected to the GC 121 from the wafer surface direction to input light, and test light can be input to the optical circuit 111, making it possible to perform testing in the wafer state. In the test device 140, the optical circuit chip 110 can be evaluated based on the measurement results of the reflected light from the optical circuit 111. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] US Patent Application Publication No. 2020 / 0232878 [Patent Document 2] US Patent Application Publication No. 2020 / 0033228 [Patent Document 3] Patent Publication No. 2021-136411 Summary of the Invention [Problem to be solved by the invention]

[0010] In the test device 140 of the conventional test system 100, in order to evaluate the polarization dependence of the optical circuit 111, both test light, TE (Transverse Electric) light and TM (Transverse Magnetic) light, are input to the optical circuit 111. However, the GC 121 in the test system 100 has polarization dependence that increases the loss of TM light, making it difficult to accurately evaluate the polarization dependence of the optical circuit 111.

[0011] In one aspect, an object of the present invention is to provide an optical device or the like that allows accurate evaluation of the polarization dependence of an optical circuit. [Means for solving the problem]

[0012] An optical device according to one embodiment includes a region in which an optical circuit and a polarization rotation mechanism are mounted. The region includes a first optical waveguide that is optically connected to the optical circuit. The region further includes a first edge coupler that is located near a boundary with a dicing line that separates the region, connects to the first optical waveguide, and allows connection to one end of the polarization rotation mechanism across the dicing line. [Effects of the Invention]

[0013] According to one aspect, the polarization dependence of an optical circuit can be accurately evaluated. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of a test system according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing an example of a wafer on which optical chips are formed. [Figure 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. [Figure 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 an optical transceiver equipped with an optical chip. [Figure 7] FIG. 7 is an explanatory diagram showing an example of a test system of a comparative example. [Figure 8] FIG. 8 is an explanatory diagram showing an example of a conventional test system. DETAILED DESCRIPTION OF THE INVENTION

[0015] Therefore, the present applicant has proposed a comparative example test system 200 that can accurately evaluate the polarization dependency of an optical circuit. Fig. 7 is an explanatory diagram showing an example of the comparative example test system 200. The test system 200 shown in Fig. 7 includes a wafer made of, for example, silicon, on which a plurality of optical chips 201 are formed, a test device 250, a first optical fiber 230A, and a second optical fiber 230B.

[0016] A plurality of optical chips 201 are formed on a wafer in a lattice arrangement. The optical chip 201 includes a first chip 210, a second chip 220, and a dicing line DL along which the first chip 210 and the second chip 220 can be cut. The first chip 210 includes an optical circuit 211, a first optical waveguide 212, and a first EC (Edge Coupler) 213. The optical circuit 211 is, for example, a circuit such as an optical transmitter or optical receiver in a digital coherent optical transceiver. The first optical waveguide 212 is a waveguide through which light is guided between the first EC 213 and the optical circuit 211. The first EC 213 is disposed near the end face of the first chip 210 on the dicing line DL side.

[0017] The second chip 220 includes a first GC (Grating Coupler) 221A, a second GC 221B, a first optical waveguide 222A, and a second optical waveguide 222B. The second chip 220 also includes a PR (Polarization Rotator) 223, a PBC (Polarization Beam Combiner) 224, a third optical waveguide 225, and a second EC 226.

[0018] The first GC 221A is disposed on the surface of the second chip 220, and is detachably connected to the first optical fiber 130A and also connected to the first optical waveguide 222A. The first optical waveguide 222A is a waveguide through which light is guided between the first GC 221A and the PR 223. The second GC 221B is disposed on the surface of the second chip 220, and is detachably connected to the second optical fiber 130B and also connected to the second optical waveguide 222B. The second optical waveguide 222B is a waveguide through which light is guided between the second GC 221B and the PBC 224.

[0019] The PR 223 rotates the polarization of the test light input from the first optical waveguide 222A by 90 degrees, and inputs the polarization-rotated test light to the PBC 224. The PBC 224 polarization-combines the test light input from the second optical waveguide 222B and the polarization-rotated test light input from the PR 223, and outputs the polarization-combined test light to the third optical waveguide 225.

[0020] The third optical waveguide 225 is a waveguide that guides light between the PBC 224 and the second EC 226. The second EC 226 is disposed near the end face on the dicing line DL side of the second chip 220. The second EC 226 is optically coupled to the first EC 213 of the first chip 210, thereby optically connecting the third optical waveguide 225 in the second chip 220 and the first optical waveguide 212 in the first chip 210.

[0021] The test apparatus 250 includes a light source 251, a polarization controller 252, an optical switch 253, a first circulator 254A, a second circulator 254B, a first optical power meter 255A, and a second optical power meter 255B.

[0022] Light source 251 is a light source that emits test light corresponding to, for example, received light, local light, or transmitted light. Polarization controller 252 polarizes the test light from light source 251 and outputs the polarized test light to optical switch 253. Polarization controller 252 controls the polarization of the test light to generate TM (Transverse Magnetic) light or TE (Transverse Electric) test light. Optical switch 253 branches and outputs the polarization-controlled test light from polarization controller 252 to first circulator 254A and second circulator 254B.

[0023] The first circulator 254A outputs the test light input from the optical switch 253 to the first optical fiber 230A, and also outputs reflected return light of the test light input from the first optical fiber 230A to the first optical power meter 255A. The first optical power meter 255A receives reflected return light of the test light from the optical circuit 211 input from the first circulator 254A and measures the power of the reflected return light.

[0024] The second circulator 254B outputs the test light input from the optical switch 253 to the second optical fiber 230B, and also outputs reflected return light of the test light input from the second optical fiber 230B to the second optical power meter 255B. The second optical power meter 255B receives reflected return light of the test light from the optical circuit 211 input from the second circulator 254B and measures the power of the reflected return light.

[0025] Next, we will explain the operation of the test system 200 of the comparative example. The polarization controller 252 in the test device 250 polarizes the test light from the light source 251 and outputs the TE light, which is the polarized test light, to the optical switch 253. The optical switch 253 branches and outputs the TE light from the polarization controller 252 to the first circulator 254A and the second circulator 254B.

[0026] The first circulator 254A outputs the polarized TE light to the first optical fiber 230A. The first GC 221A on the second chip 220 inputs the TE light from the first optical fiber 230A to the first optical waveguide 222A. The PR 223 rotates the polarization of the TE light input from the first optical waveguide 222A to TM light, and outputs the TM light after polarization rotation to the PBC 224.

[0027] The second circulator 254B outputs the polarized TE light to the second optical fiber 230B. The second GC 221B on the second chip 220 inputs the TE light from the second optical fiber 230B to the second optical waveguide 222B. The PBC 224 inputs the TE light from the second optical waveguide 222B. The PBC 224 then polarization-combines the TM light from the PR 223 and the TE light from the second optical waveguide 222B, and outputs the polarization-combined test light to the third optical waveguide 225. The second EC 226 inputs the test light input from the third optical waveguide 225 to the first EC 213 in the first chip 210.

[0028] Furthermore, the first chip 210 receives test light from the first EC 113 and outputs the received test light to the first optical waveguide 212. The first optical waveguide 212 receives the test light from the optical circuit 211. The optical circuit 211 receives reflected return light of the test light from the first optical waveguide 212. The first optical waveguide 212 receives the reflected return light from the test light from the first EC 213 and outputs the reflected return light to the second EC 226 in the second chip 220. The second EC 226 receives the reflected return light from the third optical waveguide 225.

[0029] The PBC 224 separates the reflected returning light input from the third optical waveguide 225 into TE light and TM light, and outputs the TM light to the PR 223 and the TE light to the second optical waveguide 222B. The PR 223 rotates the polarization of the TM light input from the PBC to TE light, and outputs the TE light after polarization rotation to the first optical waveguide 222A.

[0030] The first GC 221A outputs the TE light as reflected return light from the first optical waveguide 222A to the first optical fiber 230A. The first circulator 254A outputs the TE light as reflected return light input from the first optical fiber 230A to the first optical power meter 255A. The first optical power meter 255A measures the power of the reflected return light with respect to the test light from the first circulator 254A.

[0031] The second GC 221B outputs the TE light as reflected return light from the second optical waveguide 222B to the second optical fiber 230B. The second circulator 254B outputs the TE light as reflected return light input from the second optical fiber 230B to the second optical power meter 255B. The second optical power meter 255B measures the power of the reflected return light with respect to the test light from the second circulator 254B.

[0032] In the test system 200, the first optical fiber 230A is connected to the first GC 221A from the wafer surface direction to input the test light into the optical circuit 211, and the second optical fiber 230B is connected to the second GC 221B to input the test light into the optical circuit 211. As a result, testing is possible in the wafer state. Moreover, because the test light input to the first GC 221A and the second GC 221B is TE light, loss of the test light in the GCs, which has polarization dependency of TM light, can be suppressed. As a result, the test device 250 can accurately evaluate the polarization dependency of the optical circuit 211 based on the measurement results of the reflected return light from the optical circuit 211.

[0033] However, while the test system 200 exemplifies a case in which the PR 223 is disposed within the second chip 220, the PR 223 must increase the waveguide length of the optical waveguide within the PR 223 to rotate the polarization of TE light to TM light, thereby increasing the size of the second chip 220. As a result, the number of first chips 210 that can be obtained from a wafer is reduced. Therefore, there is a need for a test system that can accurately evaluate the polarization dependence of an optical circuit while ensuring the number of first chips 210 that can be obtained from a wafer. Therefore, such a test system will be described below as an embodiment.

[0034] Hereinafter, examples of optical devices and the like disclosed in the present application will be described in detail with reference to the drawings. Note that the disclosed technology is not limited to each example. Furthermore, the examples shown below may be combined as appropriate within the scope of not causing any contradiction. [Example]

[0035] FIG. 1 is an explanatory diagram showing an example of a test system 1 according to a first embodiment. The test system 1 shown in FIG. 1 includes an optical chip 2, a test device 5, and a first optical fiber 3A and a second optical fiber 3B that optically connect the optical chip 2 and the test device 5. The optical chip 2 is, for example, an optical IC chip on which an optical circuit 11 such as a digital coherent optical transceiver is mounted. The test device 5 is an evaluation device that evaluates the optical chip 2.

[0036] Fig. 2 is a plan view showing an example of a wafer 4 on which optical chips 2 are formed. The wafer 4 shown in Fig. 2 is, for example, a silicon wafer. A plurality of optical chips 2 are formed on the wafer 4 in a lattice-like arrangement. The optical chip 2 has a first chip 2A, a second chip 2B, and a dicing line DL along which the first chip 2A and the second chip 2B can be cut.

[0037] The second chip 2B is another area having a first GC (Grating Coupler) 21A, a second GC 21B, a first optical waveguide 22A, a second optical waveguide 22B, a third optical waveguide 23, and a second EC 24.

[0038] The first GC 21A is disposed on the surface of the second chip 2B, and is detachably connected to the first optical fiber 3A and also connected to the first optical waveguide 22A. The first optical waveguide 22A is a waveguide that guides light between the first GC 21A and a PR 12, which will be described later. The second GC 21B is disposed on the surface of the second chip 2B, and is detachably connected to the second optical fiber 3B and also connected to the second optical waveguide 22B. The second optical waveguide 22B is a waveguide that guides light between the second GC 21B and a third optical waveguide 17, which will be described later, within the first chip 2A.

[0039] The third optical waveguide 23 is a waveguide that guides light between the third optical waveguide 23 and a second optical waveguide 16 (described later) in the first chip 2A across the dicing line DL. The second EC 24 is disposed near the end face of the second chip 2B on the dicing line DL side. The second EC 24 is optically coupled to the first EC 15 of the first chip 2A, thereby optically connecting the third optical waveguide 23 in the second chip 2B and the first optical waveguide 14 in the first chip 2A.

[0040] The first chip 2A is an area having an optical circuit 11, a PR (Polarization Rotator) 12, a PBC (Polarization Beam Combiner) 13, a first optical waveguide 14, a first EC (Edge Coupler) 15, a second optical waveguide 16, and a third optical waveguide 17. The optical circuit 11 is, for example, a circuit such as an optical transmitter or an optical receiver in a digital coherent optical transceiver.

[0041] The PR12 is a polarization rotation unit that rotates the polarization of the test light input from the first optical waveguide 22A in the second chip 2B by 90 degrees. The PR12 inputs TE light as the test light input from the first optical waveguide 22A, and converts the input TE light into TM light by polarization rotation. The PBC13 polarization-combines the test light input from the second optical waveguide 22B in the second chip 2B and the polarization-rotated test light input from the PR12, and outputs the polarization-combined test light to the second optical waveguide 16. The PBC13 polarization-combines the TE light, which is the test light input from the second optical waveguide 22B in the second chip 2B, and the TM light input from the PR12, and outputs the polarization-combined test light to the second optical waveguide 16. The PR12 and the PBC13 are polarization rotation mechanisms.

[0042] The second optical waveguide 16 connects one end (output end) of the PBC 13 to the third optical waveguide 23 of the second chip 2B across the dicing line DL and is a waveguide through which light is guided. The second optical waveguide 16 extends from one end (output end) of the PBC 13 to the chip end face of the second chip 2B. The first optical waveguide 14 connects the optical circuit 11 and the first EC 15 and is a waveguide through which light is guided. The first EC 15 is disposed near the boundary with the dicing line DL, which allows the second chip 2B to be separated, and is connected to the first optical waveguide 14 and optically connected to the second EC 24 in the second chip 2B. In other words, the first EC 15 is connectable to one end of the PBC 13 via the second EC 24, the third optical waveguide 23, and the second optical waveguide 16 across the dicing line DL.

[0043] The test device 5 includes a light source 31, a polarization controller 32, an optical switch 33, a first circulator 34A, a second circulator 34B, a first optical power meter 35A, and a second optical power meter 35B.

[0044] The light source 31 is a light source that emits test light corresponding to, for example, received light, local light, or transmitted light. The polarization controller 32 polarizes the test light from the light source 31 and outputs the polarized test light to the optical switch 33. The polarization controller 32 controls the polarization of the test light to generate TM light or TM test light. The optical switch 33 branches and outputs the polarization-controlled test light from the polarization controller 32 to a first circulator 34A and a second circulator 34B.

[0045] The first circulator 34A outputs the test light input from the optical switch 33 to the first optical fiber 3A, and also outputs reflected return light of the test light input from the first optical fiber 3A to the first optical power meter 35A. The first optical power meter 35A receives reflected return light of the test light from the optical circuit 11 input from the first circulator 34A and measures the power of the reflected return light.

[0046] The second circulator 34B outputs the test light input from the optical switch 33 to the second optical fiber 3B, and also outputs reflected return light of the test light input from the second optical fiber 3B to the second optical power meter 35B. The second optical power meter 35B receives reflected return light of the test light from the optical circuit 11 and measures the power of the reflected return light.

[0047] Next, the operation of the test system 1 of the first embodiment will be described. First, the wafer 4 is placed on the wafer prober. Then, the second chip 2B in the optical chip 2 on the wafer 4 moves, and the test operation starts in a state where an optical connection is established between the first GC 21A in the second chip 2B and the first optical fiber 3A, and between the second GC 21B and the second optical fiber 3B.

[0048] The polarization controller 32 in the test device 5 polarizes the test light from the light source 31 and outputs TE light, which is the polarized test light, to the optical switch 33. The optical switch 33 branches the TE light from the polarization controller 32 and outputs it to a first circulator 34A and a second circulator 34B.

[0049] The first circulator 34A outputs the polarized TE light to the first optical fiber 3A. The first GC 21A on the second chip 2B inputs the TE light from the first optical fiber 3A to the first optical waveguide 22A. The PR12 rotates the polarization of the TE light input from the first optical waveguide 22A to TM light, and outputs the TM light after the polarization rotation to the PBC13.

[0050] The second circulator 34B outputs the polarized TE light to the second optical fiber 3B. The second GC 21B on the second chip 2B inputs the TE light from the second optical fiber 3B to the second optical waveguide 22B. The second optical waveguide 22B inputs the TE light across the dicing line DL to the third optical waveguide 17 in the first chip 2A. The PBC 13 inputs the TE light from the third optical waveguide 17. Then, the PBC 13 polarization-combines the TM light from the PR 12 and the TE light from the third optical waveguide 17, and outputs the polarization-combined test light to the second optical waveguide 16.

[0051] The second optical waveguide 16 inputs the test light to the third optical waveguide 23 in the second chip 2B across the dicing line DL. The second EC 24 inputs the test light input from the third optical waveguide 23 to the first EC 15 in the first chip 2A.

[0052] Furthermore, the first chip 2A inputs test light from the first EC 15 and outputs the input test light to the first optical waveguide 14. The first optical waveguide 14 inputs the test light to the optical circuit 11. The optical circuit 11 outputs reflected return light of the test light to the first optical waveguide 14. The first optical waveguide 14 inputs the reflected return light to the second EC 24 in the second chip 2B through the first EC 15. The second EC 24 outputs the reflected return light to the third optical waveguide 23. The third optical waveguide 23 outputs the reflected return light to the second optical waveguide 16 in the first chip 2A across the dicing line DL.

[0053] The PBC 13 separates the reflected return light input from the second optical waveguide 16 into TE light and TM light, outputs the TM light to the PR 12, and outputs the TE light to the third optical waveguide 17. The PR 12 rotates the polarization of the TM light input from the PBC 13 to TE light, and outputs the TE light after polarization rotation to the first optical waveguide 22A in the second chip 2B.

[0054] The first GC 21A outputs the TE light as the reflected return light from the first optical waveguide 22A to the first optical fiber 3A. The first circulator 34A outputs the TE light as the reflected return light input from the first optical fiber 3A to the first optical power meter 35A. The first optical power meter 35A measures the power of the reflected return light with respect to the test light from the first circulator 34A.

[0055] The third optical waveguide 17 outputs the TE light as reflected return light separated from the PBC 13 to the second optical waveguide 22B in the second chip 2B across the dicing line DL. The second GC 21B outputs the TE light as reflected return light from the second optical waveguide 22B to the second optical fiber 3B. The second circulator 34B outputs the TE light as reflected return light input from the second optical fiber 3B to the second optical power meter 35B. The second optical power meter 35B measures the power of the reflected return light with respect to the test light from the second circulator 34B.

[0056] Then, when the test device 5 completes the measurement and evaluation of the power of the reflected return light of the first chip 2A in all the optical chips 2 in the row unit on the wafer 4 shown in FIG. 2, it dices all the optical chips 2 in the row unit along the dicing line DL. Then, it starts the measurement of the reflected return light for each optical chip 2 in the next row unit, and continues until the measurement operation for all the optical chips 2 on the wafer 4 is completed. Furthermore, by dicing along the dicing line DL for each optical chip 2 in the wafer 4, the first chip 2A and the second chip 2B in the optical chip 2 are separated, and the first chip 2A with the first EC 15 exposed can be obtained. As a result, the optical circuit 11 in the first chip 2A can be connected to other optical devices, such as optical fibers used for operation, via the first EC 15.

[0057] In the test system 1, the first optical fiber 3A is connected to the first GC 21A from the wafer surface direction to input the test light into the optical circuit 11, and the second optical fiber 3B is connected to the second GC 21B to input the test light into the optical circuit 11. As a result, testing is possible in the wafer state. Moreover, because the test light input into the first GC 21A and the second GC 21B is TE light, loss of the test light in the GCs, which has polarization dependency of TM light, can be suppressed. As a result, the test equipment 5 can accurately evaluate the polarization dependency of the optical circuit 11 based on the measurement results of the reflected light from the optical circuit 11.

[0058] Moreover, since the other end of PR12 in first chip 2A is arranged across dicing line DL, the area of ​​second chip 2B is made smaller than that of second chip 220 used in the comparative example. As a result, the number of first chips 2A that can be obtained on wafer 4 can be increased.

[0059] The second optical waveguide 16 is purposely designed to cross the dicing line DL and pass through the third optical waveguide 23 to be connectable to the first EC 15 at the second EC 24. As a result, after cutting at the dicing line DL after testing, the PR 12 and PBC 13 are no longer used, so the only point connected to the optical circuit 11 is the first EC 15, enabling optical connection between the optical fiber used for operation and the optical circuit 11.

[0060] For convenience of explanation, the test system 1 of Example 1 is exemplified as having the PR 12 and PBC 13 arranged on the first chip 2A. However, instead of the PR 12 and PBC 13, a PRC may be mounted on the first chip 2A, and this embodiment will be described below as Example 2. [Example]

[0061] 3 is an explanatory diagram showing an example of a test system 1A of Example 2. Note that the test system 1A of Example 2 differs from the test system 1 of Example 1 in that a PRC (Polarization Rotator Combiner) 18 is mounted on the first chip 2A1 instead of the PR 12 and PBC 13. Note that the PRC 18 is a polarization rotation mechanism.

[0062] The other end of the PRC 18, which is the input end of the PRC 18, is disposed on the second chip 2B across the dicing line DL. The PRC 18 rotates the polarization of the test light input from the first optical waveguide 22A1 in the second chip 2B by 90 degrees. Furthermore, the PRC 18 polarization-combines the test light input from the second optical waveguide 22B1 in the second chip 2B and the polarization-rotated test light, and outputs the polarization-combined test light to the second optical waveguide 16.

[0063] The PRC 18 receives TE light as test light input from the first optical waveguide 22A1, rotates the polarization of the input TE light, and converts it into TM light. The PRC 18 then polarization-combines the TE light, which is the test light input from the second optical waveguide 22B1 in the second chip 2B, with the TM light after polarization rotation, and outputs the polarization-combined test light to the second optical waveguide 16.

[0064] Next, the operation of the test system 1A of the second embodiment will be described. First, the wafer 4 is placed on the wafer prober. Then, the second chip 2B in the optical chip 2 on the wafer 4 moves, and the test operation starts in a state where an optical connection is established between the first GC 21A in the second chip 2B and the first optical fiber 3A, and between the second GC 21B and the second optical fiber 3B.

[0065] The polarization controller 32 in the test device 5 polarizes the test light from the light source 31 and outputs TE light, which is the polarized test light, to the optical switch 33. The optical switch 33 branches the TE light from the polarization controller 32 and outputs it to a first circulator 34A and a second circulator 34B.

[0066] The first circulator 34A outputs the polarized TE light to the first optical fiber 3A. The first GC 21A on the second chip 2B inputs the TE light from the first optical fiber 3A to the first optical waveguide 22A1. The PRC 18 rotates the polarization of the TE light input from the first optical waveguide 22A1 to TM light.

[0067] The second circulator 34B outputs the polarized TE light to the second optical fiber 3B. The second GC 21B on the second chip 2B inputs the TE light from the second optical fiber 3B to the second optical waveguide 22B1. The PRC 18 inputs the TE light from the second optical waveguide 22B1. The PRC 18 then polarization-combines the TM light after polarization rotation and the TE light from the second optical waveguide 22B1, and outputs the polarization-combined test light to the second optical waveguide 16. The second optical waveguide 16 inputs the test light to the third optical waveguide 23 in the second chip 2B across the dicing line DL. The second EC 24 inputs the test light input from the third optical waveguide 23 to the first EC 15 in the first chip 2A1.

[0068] Furthermore, the first chip 2A1 receives test light from the first EC 15 and outputs the received test light to the first optical waveguide 14. The first optical waveguide 14 receives the test light from the optical circuit 11. The optical circuit 11 receives reflected return light from the test light and outputs it to the first optical waveguide 14. The first optical waveguide 14 receives the reflected return light from the second chip 2B through the first EC 15 and outputs it to the second EC 24 in the second chip 2B. The second EC 24 outputs the reflected return light to the third optical waveguide 23. The third optical waveguide 23 receives the reflected return light from the second optical waveguide 16 in the first chip 2A1 across the dicing line DL.

[0069] The PRC 18 separates the reflected return light input from the second optical waveguide 16 into TE light and TM light, rotates the polarization of the input TM light to convert it into TE light, and outputs the TE light after polarization rotation to the first optical waveguide 22A1 in the second chip 2B.

[0070] The first GC 21A outputs the TE light as the reflected return light from the first optical waveguide 22A1 to the first optical fiber 3A. The first circulator 34A outputs the TE light as the reflected return light input from the first optical fiber 3A to the first optical power meter 35A. The first optical power meter 35A measures the power of the reflected return light with respect to the test light from the first circulator 34A.

[0071] The PRC 18 outputs the TE light as the separated reflected return light to the second optical waveguide 22B1 in the second chip 2B. The second GC 21B outputs the TE light as the reflected return light from the second optical waveguide 22B1 to the second optical fiber 3B. The second circulator 34B outputs the TE light as the reflected return light input from the second optical fiber 3B to the second optical power meter 35B. The second optical power meter 35B measures the power of the reflected return light with respect to the test light from the second circulator 34B.

[0072] Then, when the test device 5 completes the measurement and evaluation of the power of the reflected return light of the first chips 2A1 in all the optical chips 2 in a row on the wafer 4, it dices all the optical chips 2 in a row along the dicing line DL. Then, it starts the measurement of the reflected return light for each optical chip 2 in the next row, and continues until the measurement of all the optical chips 2 on the wafer 4 is completed. Furthermore, by dicing along the dicing line DL for each optical chip 2 in the wafer 4, the first chip 2A1 and the second chip 2B in the optical chip 2 are separated, and the first chip 2A1 with the first EC 15 exposed can be obtained. As a result, the optical circuit 11 in the first chip 2A1 can be connected to other optical devices, such as optical fibers used for operation, via the first EC 15.

[0073] In the test system 1A, the first optical fiber 3A is connected to the first GC 21A from the wafer surface direction to input the test light into the optical circuit 11, and the second optical fiber 3B is connected to the second GC 21B to input the test light into the optical circuit 11. As a result, testing is possible in the wafer state. Moreover, because the test light input into the first GC 21A and the second GC 21B is TE light, loss of the test light in the GCs, which has polarization dependency of TM light, can be suppressed. As a result, the test equipment 5 can accurately evaluate the polarization dependency of the optical circuit 11 based on the measurement results of the reflected light from the optical circuit 11.

[0074] Moreover, since the other end of the PRC 18 in the first chip 2A1 is arranged across the dicing line DL, the area of ​​the second chip 2B is made smaller than that of the second chip 220 used in the comparative example. As a result, the number of first chips 2A1 that can be obtained from the wafer 4 can be increased.

[0075] The second optical waveguide 16 is designed to be connectable to the first EC 15 via the second EC 24 by crossing the dicing line DL and passing through the third optical waveguide 23. As a result, since the PRC 18 is not used after cutting at the dicing line DL after testing, the only point connected to the optical circuit 11 is the first EC 15, and optical connection can be made between the optical fiber used for operation and the optical circuit 11.

[0076] In the test system 1A of Example 2, the input terminal (other terminal) of the PRC 18 is arranged across the dicing line DL, but this is not limited to this, and an embodiment thereof will be described below as Example 3. [Example]

[0077] 4 is an explanatory diagram showing an example of a test system 1B of Example 3. Note that the test system 1A of Example 2 and the test system 1B of Example 3 differ in that the entire PRC 18A is mounted on the first chip 2A2 without spanning the dicing line DL.

[0078] The PRC 18A rotates the polarization of the test light input from the first optical waveguide 22A in the second chip 2B by 90 degrees, and polarization-combines the test light after the polarization rotation with the test light input from the second optical waveguide 22B in the second chip 2B. Then, the PRC 18A outputs the polarization-combined test light to the second optical waveguide 16.

[0079] The PRC 18A receives TE light as test light input from the first optical waveguide 22A, rotates the polarization of the input TE light, and converts it into TM light. The PRC 18A then polarization-combines the TE light, which is test light input from the second optical waveguide 22B in the second chip 2B, and the TM light after polarization rotation, and outputs the polarization-combined test light to the second optical waveguide 16.

[0080] Next, the operation of the test system 1B of the third embodiment will be described. The first GC 21A on the second chip 2B inputs the TE light from the first optical fiber 3A to the first optical waveguide 22A. The PRC 18A performs polarization rotation on the TE light input from the first optical waveguide 22A to convert it into TM light.

[0081] The second GC 21B on the second chip 2B inputs the TE light from the second optical fiber 3B to the second optical waveguide 22B. The PRC 18A inputs the TE light from the second optical waveguide 22B. The PRC 18A then polarization-combines the TM light after polarization rotation and the TE light from the second optical waveguide 22B, and outputs the polarization-combined test light to the second optical waveguide 16. The second optical waveguide 16 inputs the test light to the third optical waveguide 23 in the second chip 2B across the dicing line DL. The second EC 24 inputs the test light input from the third optical waveguide 23 to the first EC 15 in the first chip 2A2.

[0082] Furthermore, the first chip 2A2 receives test light from the first EC 15 and outputs the received test light to the first optical waveguide 14. The first optical waveguide 14 receives the test light from the optical circuit 11. The optical circuit 11 receives reflected return light from the test light and outputs it to the first optical waveguide 14. The first optical waveguide 14 receives the reflected return light from the second chip 2B through the first EC 15 and outputs it to the second EC 24 in the second chip 2B. The second EC 24 outputs the reflected return light to the third optical waveguide 23. The third optical waveguide 23 receives the reflected return light from the second optical waveguide 16 in the first chip 2A2 and crosses the dicing line DL.

[0083] The PRC 18A separates the reflected return light input from the second optical waveguide 16 into TE light and TM light, rotates the polarization of the input TM light to convert it into TE light, and outputs the TE light after polarization rotation to the first optical waveguide 22A in the second chip 2B.

[0084] The first GC 21A outputs the TE light as the reflected return light from the first optical waveguide 22A to the first optical fiber 3A. The first circulator 34A outputs the TE light as the reflected return light input from the first optical fiber 3A to the first optical power meter 35A. The first optical power meter 35A measures the power of the reflected return light with respect to the test light from the first circulator 34A.

[0085] The PRC 18A outputs the TE light as the separated reflected return light to the second optical waveguide 22B in the second chip 2B. The second GC 21B outputs the TE light as the reflected return light from the second optical waveguide 22B to the second optical fiber 3B. The second circulator 34B outputs the TE light as the reflected return light input from the second optical fiber 3B to the second optical power meter 35B. The second optical power meter 35B measures the power of the reflected return light with respect to the test light from the second circulator 34B.

[0086] Then, when the test device 5 completes the measurement and evaluation of the power of the reflected return light of the first chips 2A2 in all the optical chips 2 in a row on the wafer 4, it dices all the optical chips 2 in a row along the dicing line DL. Then, it starts the measurement of the reflected return light for each optical chip 2 in the next row, and continues until the measurement of all the optical chips 2 on the wafer 4 is completed. Furthermore, by dicing along the dicing line DL for each optical chip 2 in the wafer 4, the first chip 2A2 and the second chip 2B in the optical chip 2 are separated, and the first chip 2A2 with the first EC 15 exposed can be obtained. As a result, the optical circuit 11 in the first chip 2A2 can be connected to other optical devices, such as optical fibers used for operation, via the first EC 15.

[0087] In the test system 1B of the third embodiment, the first optical fiber 3A is connected to the first GC 21A from the wafer surface direction to input the test light to the optical circuit 11, and the second optical fiber 3B is connected to the second GC 21B to input the test light to the optical circuit 11. As a result, testing in the wafer state is possible. Moreover, since the test light input to the first GC 21A and the second GC 21B is TE light, loss of the test light in the GCs, which has polarization dependency of TM light, can be suppressed. As a result, the test device 5 can accurately evaluate the polarization dependency of the optical circuit 11 based on the measurement results of the reflected light from the optical circuit 11.

[0088] Moreover, since the first chip 2A2 mounts the entire PRC 18A, the area of ​​the second chip 2B is made smaller than that of the second chip 220 used in the comparative example. As a result, the number of first chips 2A2 that can be obtained on the wafer 4 can be increased.

[0089] The second optical waveguide 16 is designed to cross the dicing line DL and pass through the third optical waveguide 23 to be connectable to the first EC 15 at the second EC 24. As a result, since the PRC 18A is not used after being cut at the dicing line DL after testing, the only point connected to the optical circuit 11 is the first EC 15, and optical connection can be made between the optical fiber used for operation and the optical circuit 11.

[0090] In the test system 1A of Example 2, an example is given in which the first GC 21A and the second GC 21B are arranged on the second chip 2B1, but this is not limited to this, and an embodiment thereof will be described below as Example 4. [Example]

[0091] 5 is an explanatory diagram showing an example of a test system 1C of Example 4. The test system 1C of Example 4 differs from the test system 1A of Example 2 in that the first GC 19A and the second GC 19B are arranged on the first chip 2A3. Another difference is that one end, which is the output end of the PRC 18B, is arranged on the second chip 2B1 across the dicing line DL.

[0092] The first GC 19A is detachably connected to the first optical fiber 3A and is also connected to a fourth optical waveguide 17A that is connected to the input end of the PRC 18B. The fourth optical waveguide 17A is disposed on the first chip 2A3 and optically connects the first GC 19A and the input end of the PRC 18B.

[0093] The second GC 19B is detachably connected to the second optical fiber 3B and is connected to a fifth optical waveguide 17B that is connected to the input end of the PRC 18B. The fifth optical waveguide 17B is disposed on the first chip 2A3 and optically connects the second GC 19B and the input end of the PRC 18B.

[0094] The PRC 18B receives TE light as test light input from the fourth optical waveguide 17A, rotates the polarization of the input TE light, and converts it into TM light. Furthermore, the PRC 18B polarization-combines the TE light, which is the test light input from the fifth optical waveguide 17B, and the TM light after polarization rotation, and outputs the polarization-combined test light to the third optical waveguide 23 in the second chip 2B1.

[0095] Next, the operation of the test system 1C of the fourth embodiment will be described. First, the wafer 4 is placed on the wafer prober. Then, the second chip 2B1 in the optical chip 2 on the wafer 4 moves, and the test operation starts in a state where an optical connection is established between the first GC 19A in the first chip 2A3 and the first optical fiber 3A, and between the second GC 19B and the second optical fiber 3B.

[0096] The polarization controller 32 in the test device 5 polarizes the test light from the light source 31 and outputs TE light, which is the polarized test light, to the optical switch 33. The optical switch 33 branches the TE light from the polarization controller 32 and outputs it to a first circulator 34A and a second circulator 34B.

[0097] The first circulator 34A outputs the polarized TE light to the first optical fiber 3A. The first GC 19A on the first chip 2A3 inputs the TE light from the first optical fiber 3A to the fourth optical waveguide 17A. The PRC 18B rotates the polarization of the TE light input from the fourth optical waveguide 17A to TM light.

[0098] The second circulator 34B outputs the polarized TE light to the second optical fiber 3B. The second GC 19B on the first chip 2A3 inputs the TE light from the second optical fiber 3B to the fifth optical waveguide 17B. The PRC 18B inputs the TE light from the fifth optical waveguide 17B. The PRC 18B then polarization-combines the TM light after polarization rotation and the TE light from the fifth optical waveguide 17B, and outputs the polarization-combined test light to the third optical waveguide 23. The second EC 24 inputs the test light input from the third optical waveguide 23 to the first EC 15 in the first chip 2A3.

[0099] Furthermore, the first chip 2A3 inputs test light from the first EC 15 and outputs the input test light to the first optical waveguide 14. The first optical waveguide 14 inputs the test light to the optical circuit 11. The optical circuit 11 outputs reflected return light of the test light to the first optical waveguide 14. The first optical waveguide 14 inputs the reflected return light to the second EC 24 in the second chip 2B1 through the first EC 15. The second EC 24 outputs the reflected return light to the third optical waveguide 23. The third optical waveguide 23 outputs the reflected return light to the PRC 18B.

[0100] The PRC 18B separates the reflected return light input from the third optical waveguide 23 into TE light and TM light, rotates the polarization of the input TM light to convert it into TE light, and outputs the TE light after polarization rotation to the fourth optical waveguide 17A.

[0101] The first GC 19A outputs the TE light as the reflected return light from the fourth optical waveguide 17A to the first optical fiber 3A. The first circulator 34A outputs the TE light as the reflected return light input from the first optical fiber 3A to the first optical power meter 35A. The first optical power meter 35A measures the power of the reflected return light with respect to the test light from the first circulator 34A.

[0102] The PRC 18B outputs the TE light as the separated reflected return light to the fifth optical waveguide 17B. The second GC 19B outputs the TE light as the reflected return light from the fifth optical waveguide 17B to the second optical fiber 3B. The second circulator 34B outputs the TE light as the reflected return light input from the second optical fiber 3B to the second optical power meter 35B. The second optical power meter 35B measures the power of the reflected return light with respect to the test light from the second circulator 34B.

[0103] Then, when the test device 5 completes the measurement and evaluation of the power of the reflected return light of the first chips 2A3 in all the optical chips 2 in a row on the wafer 4, it dices all the optical chips 2 in a row along the dicing line DL. Then, it starts the measurement of the reflected return light for each optical chip 2 in the next row, and continues until the measurement of all the optical chips 2 on the wafer 4 is completed. Furthermore, by dicing along the dicing line DL for each optical chip 2 in the wafer 4, the first chip 2A3 and the second chip 2B1 in the optical chip 2 are separated, and the first chip 2A3 with the first EC 15 exposed can be obtained. As a result, the optical circuit 11 in the first chip 2A3 can be connected to other optical devices, such as optical fibers used for operation, via the first EC 15.

[0104] In the test system 1C, the first optical fiber 3A is connected to the first GC 19A from the wafer surface direction to input the test light into the optical circuit 11, and the second optical fiber 3B is connected to the second GC 19B to input the test light into the optical circuit 11. As a result, testing is possible in the wafer state. Moreover, because the test light input into the first GC 19A and the second GC 19B is TE light, loss of the test light in the GCs, which has polarization dependency of TM light, can be suppressed. As a result, the test equipment 5 can accurately evaluate the polarization dependency of the optical circuit 11 based on the measurement results of the reflected light from the optical circuit 11.

[0105] Furthermore, one end of the PRC 18B in the first chip 2A3 is positioned across the dicing line DL, and the first GC 19A and second GC 19B are positioned on the first chip 2A3. The surface area of ​​the second chip 2B1 is made smaller than that of the second chip 220 used in the comparative example. As a result, the number of first chips 2A3 that can be obtained from the wafer 4 can be increased.

[0106] One end of the PRC 18B is purposely designed to cross the dicing line DL and pass through the third optical waveguide 23 to be connectable to the first EC 15 via the second EC 24. As a result, since the PRC 18B is not used after being cut at the dicing line DL after testing, the only point that is connected to the optical circuit 11 is the first EC 15, enabling optical connection between the optical fiber used for operation and the optical circuit 11.

[0107] FIG. 6 is an explanatory diagram showing an example of an optical transceiver 50 equipped with an optical chip 2. The optical transceiver 50 shown in FIG. 6 includes a DSP (Digital Signal Processor) 51, an optical transmitter 53 for transmitting an optical signal, and an optical receiver 54 for receiving the optical signal. The optical receiver 54 includes an optical receiving unit 54A for converting the optical signal into an electrical signal, and is, for example, the first chip 2A after disconnecting a second chip 2B such as a digital coherent receiver. The DSP 51 digitally converts each electrical signal input from the optical receiver 54. The optical transmitter 53 includes an optical modulation unit 53A for modulating light in response to the electrical signal from the DSP 51, and is, for example, the first chip 2A after disconnecting a second chip 2B such as a digital coherent transmitter.

[0108] For convenience of explanation, the optical fibers 3A and 3B are fixed on a wafer prober, and the wafer 4 mounted on the wafer prober moves up, down, left, and right relative to the optical fibers 3A and 3B. However, the optical fibers 3A and 3B may also move up, down, left, and right on the wafer 4, and modifications can be made as appropriate.

[0109] Furthermore, the first chip 2A is exemplified as a digital coherent transceiver, but is not limited to the digital coherent system, and may be an optical receiver or optical transmitter of another system, and can be changed as appropriate.

[0110] Furthermore, the components of each unit shown in the figure do 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.

[0111] 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), MCU (Micro Controller Unit), or DSP). Needless to say, 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 MCU), or on hardware using wired logic. [Explanation of symbols]

[0112] 2 Optical chip 2A First Chip 2B Second Chip 11 Optical circuit 12 PR 13 PBC 14 First optical waveguide 15 First EC 16 Second optical waveguide 21A 1st GC 21B Second GC 23 Third Optical Waveguide 24 Second EC DL dicing line

Claims

1. An optical device having an area in which an optical circuit and a polarization rotation mechanism are mounted, The region is a first optical waveguide optically connected to the optical circuit; a first edge coupler that is arranged near a boundary with a dicing line that allows the regions to be separated, the first edge coupler being connected to the first optical waveguide and being connectable to one end of the polarization rotation mechanism across the dicing line; An optical device comprising:

2. The polarization rotation mechanism includes: a polarization rotation unit that converts input TE (Transverse Electric) light into TM (Transverse Magnetic) light; a polarization combining unit that combines the input TE light and the TM light converted by the polarization rotation unit and outputs the combined light; 2. The optical device according to claim 1, wherein:

3. The polarization rotation mechanism includes: the other end of the polarization rotation mechanism is disposed across the dicing line, The region is The optical device according to claim 1, characterized in that it has a second optical waveguide that optically connects between the vicinity of the boundary with the dicing line and one end of the polarization rotation mechanism, and that connects to the first edge coupler across the dicing line.

4. a second region that can be separated from the first region by the dicing line; The other region is a grating coupler optically connected to the other end of the polarization rotation mechanism; a third optical waveguide optically connected to the second optical waveguide; a second edge coupler that is disposed near the boundary with the dicing line and optically connects the third optical waveguide and the first edge coupler; 4. The optical device according to claim 3, wherein:

5. The region is 2. The optical device according to claim 1, further comprising a grating coupler optically connected to the other end of the polarization rotation mechanism.

6. a second region that can be separated from the first region by the dicing line; The other region is a third optical waveguide optically connected to one end of the polarization rotation mechanism; a second edge coupler that is disposed near the boundary with the dicing line and optically connects the third optical waveguide and the first edge coupler; 4. The optical device according to claim 3, wherein:

7. An optical transmitter incorporating an optical device having an optical circuit including an optical modulation unit that optically modulates light using a transmission signal and transmits transmission light, The optical device is An optical device having an area in which an optical circuit and a polarization rotation mechanism are mounted, The region is a first optical waveguide optically connected to the optical circuit; a first edge coupler that is arranged near a boundary with a dicing line that allows the regions to be separated, the first edge coupler being connected to the first optical waveguide and being connectable to one end of the polarization rotation mechanism across the dicing line; An optical transmitter comprising:

8. An optical receiver incorporating an optical device having an optical circuit including an optical receiving unit that receives a reception signal from received light using light, The optical device is An optical device having an area in which an optical circuit and a polarization rotation mechanism are mounted, The region is a first optical waveguide optically connected to the optical circuit; a first edge coupler that is arranged near a boundary with a dicing line that allows the regions to be separated, the first edge coupler being connected to the first optical waveguide and being connectable to one end of the polarization rotation mechanism across the dicing line; An optical receiver comprising:

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