Multi-polarized optical apparatus

Abstract

The invention relates to a multi-polarized optical device. The optical device includes a first chip and a second chip. The first chip includes a first polarized signal optical port, a second polarized signal optical port, and one or more optical elements coupled to the first polarized signal optical port and the second polarized signal optical port. The second chip comprises a first polarized signal optical port coupled with the first polarized signal optical port of the first chip, a second polarized signal optical port coupled with the second polarized signal optical port of the first chip, and a multi-polarized signal optical port; and a polarization rotation and combination element coupling the first polarization signal optical port and the second polarization signal optical port with the multi-polarization signal optical port. The first chip includes a first semiconductor chip material. The second chip includes a second semiconductor chip material different from the first semiconductor chip material.

Description

Technical Field

[0001] Aspects of the present disclosure relate to optical communication systems, optical transmitters, and optical receivers. Background Art

[0002] An optical transmitter can use multiple polarized signals to transmit data. In this way, the optical transmitter can better utilize the bandwidth of the optical fiber used to guide the transmission signal. For example, the optical transmitter can transmit a dual-polarized signal, which includes first data modulated on a transverse electric (TE) polarized signal and second data modulated in a transverse magnetic (TM) polarized signal. To this end, such an optical transmitter can modulate the first data on a first TE polarized signal and can modulate the second data in a second TE polarized signal. The optical transmitter can rotate the modulated first TE polarized signal by 90° to obtain a modulated TM polarized signal. The optical transmitter can combine the modulated TM polarized signal with the modulated second TE polarized signal and inject the combined signal into the optical fiber. In this way, the optical transmitter can transmit data on an optical fiber via signals with multiple polarizations.

[0003] Typically, aspects of an optical transmitter (e.g., modulators, amplifiers, etc.) can be implemented via a semiconductor chip. However, discrete components external to the semiconductor chip (e.g., lenses, wave plates, etc.) can provide aspects of the optical transmitter for which the semiconductor chip is not suitable. For example, III-V semiconductor devices, such as indium phosphide (InP) devices, sufficiently confine the optical mode of a signal to the horizontal dimension. However, due to the lack of a native oxide, III-V semiconductor devices provide weak vertical confinement of the signal. Thus, TE polarized signals are well confined in III-V semiconductor devices, but TM polarized signals are not. Therefore, III-V semiconductor devices are generally suitable for implementing modulators, amplifiers, and possibly other aspects of an optical transmitter, but provide a poor carrier for guiding and manipulating TM polarized signals. Consequently, a single III-V semiconductor device or chip has proven to be an impractical medium for implementing multi-polarized optical transmitters. Summary of the Invention

[0004] Optical devices and related methods are shown in at least one of the accompanying drawings and / or described in conjunction with at least one of the accompanying drawings and are more fully set forth in the claims. In various embodiments, the optical device may include a first chip or semiconductor optical device (e.g., a III-V semiconductor chip) coupled to a second chip or semiconductor optical device (e.g., a silicon photonics (SiP) chip). In various embodiments, the first chip may include a plurality of modulators, each modulator modulating data on a corresponding polarization signal. In particular, each of the modulated signals generated by the plurality of modulators may have the same polarization. The first chip may also include an amplifier that amplifies the modulated signal before providing the modulated signal to the second chip. The second chip may rotate one or more modulated signals received from the first chip and combine the modulated signals into a combined signal including modulated signals of different polarizations.

[0005] These and other advantages, various aspects and novel features of the present disclosure, as well as details of illustrated embodiments thereof, will be more fully understood from the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The various features and advantages of the present disclosure may be more readily understood by reference to the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like structural elements.

[0007] Figure 1 An optical communication system including an optical device and an optical fiber array according to aspects of the present disclosure is shown.

[0008] Figure 2 An optical communication system including an optical device and an optical fiber array according to aspects of the present disclosure is shown.

[0009] Figure 3 An optical communication system including an optical device and an optical fiber array according to aspects of the present disclosure is shown.

[0010] Figure 4 An optical communication system including an optical device and an optical fiber array according to aspects of the present disclosure is shown.

[0011] Figures 5A to 5C An optical communication system including an optical device and an optical fiber array according to aspects of the present disclosure is shown.

[0012] Figure 6 An alignment device for assisting in aligning optical fibers of an optical fiber array with optical ports of an optical device is shown.

[0013] Figure 7 An alignment device for assisting in aligning optical fibers of an optical fiber array with optical ports of an optical device is shown. DETAILED DESCRIPTION

[0014] The following discussion provides various examples of optical communication systems, optical transmitters, optical receivers, and related methods. Such examples are non-limiting, and the scope of the appended claims should not be limited to the specific examples disclosed. In the following discussion, the terms "example" and "such as" are non-limiting.

[0015] These figures illustrate the general construction method. Descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. In addition, the elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be exaggerated relative to other elements to help improve understanding of the examples discussed in this disclosure. The same reference numerals in different figures represent the same elements.

[0016] The term "and / or" refers to any one or more items in a list connected by "and / or". For example, "x and / or y" refers to any element in the three-element set {(x), (y), (x,y)}. In other words, "x and / or y" means "one or both of x and y". As another example, "x, y, and / or z" refers to any element in the seven-element set {(x), (y), (z), (x,y), (x,z), (y,z), (x,y,z)}. In other words, "x, y and / or z" means "one or more of x, y, and z".

[0017] The terms “comprise,” “comprising,” “include,” and / or “including” are “open” terms that specify the presence of stated features but do not preclude the presence or addition of one or more other features.

[0018] The terms "first," "second," etc., may be used herein to describe various elements, but these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, for example, a first element discussed in this disclosure could be referred to as a second element without departing from the teachings of this disclosure.

[0019] Unless otherwise specified, the term "coupled" can be used to describe two elements that are in direct contact with each other or to describe two elements that are indirectly connected by one or more other elements. For example, if element A is coupled to element B, element A can be directly in contact with element B or indirectly connected to element B through an intervening element C. Similarly, the terms "over" or "on" can be used to describe two elements that are in direct contact with each other or to describe two elements that are indirectly connected by one or more other elements.

[0020] In various embodiments, an optical communication system may include an optical transmitter configured to transmit modulated signals having multiple polarizations and / or an optical receiver configured to receive modulated signals having multiple polarizations. To this end, the optical transmitter may include a first chip and a second chip. The first chip may modulate data onto the corresponding polarized signals and may amplify the modulated signals. The second chip may receive the modulated signals, rotate the polarization of one or more of the modulated signals, and combine the signals to obtain modulated signals having multiple polarizations. The second chip may inject the combined signal into an optical fiber of the optical fiber array.

[0021] Now refer to Figure 1 , showing aspects of an optical communication system 10. In particular, Figure 1 An optical transmitter 20 and an optical fiber array 300 of an optical communication system 10 are shown. As shown, the optical transmitter 20 includes a first chip 100 made of a first semiconductor chip material and a second chip 200 made of a second semiconductor chip material. In various embodiments, the first chip 100 includes an indium phosphide (InP) chip, and the second chip 200 includes a silicon photonic chip (SiP) having a silicon-on-insulator structure. Although InP is used as an example semiconductor chip material for the first chip 100 of the present disclosure, the same principles apply to other III-V semiconductor chip materials. Therefore, the first chip 100 can utilize other III-V semiconductor chip materials, such as gallium arsenide (GaAs).

[0022] The first chip 100 may include one or more optical elements, such as a modulator 130 and an amplifier 140 coupled to an optical port 150 (e.g., IN, TEO1, TEO2). Typically, the first chip 100 may include a signal input port IN for receiving an unmodulated laser or an unmodulated signal. The first chip 100 may further include a splitter 160, a waveguide 170, etc., which split the unmodulated signal and guide the unmodulated signal to each modulator 130. The first chip 100 may also include a modulation signal waveguide 180, which guides the modulated signal from the modulator 130 to the corresponding optical ports TEO1, TEO2. To this end, each modulator 130 can generate a modulated signal by modulating the unmodulated signal it receives based on the corresponding data stream.

[0023] In some embodiments, the first chip 100 may include processing circuitry and / or other data sources that generate and provide a corresponding data stream to each modulator 130. In other embodiments, the data streams may be generated off-chip and received from one or more external data sources via one or more inputs of the first chip 100.

[0024] In some embodiments, the modulation signal waveguide 180 can guide the modulation signal to the first modulation signal port TEO1 and the second modulation signal port TEO2, respectively. In other embodiments, the modulation signal waveguide 180 can guide the modulation signal through the amplifier 140, which amplifies the modulation signal before guiding the modulation signal to its corresponding modulation signal port TEO1, TEO2.

[0025] In various embodiments, a laser or other signal source can provide an unmodulated signal having a first polarization to the signal input port IN of the first chip 100, and the first polarization is suitable for the semiconductor chip material of the first chip 100. As described above, InP chips are very suitable for limiting and processing TE polarization signals. Therefore, in the example InP embodiment of the first chip 100, a laser or other signal source can provide an unmodulated TE polarization signal to the signal input port IN. In addition, the modulator 130, amplifier 140, splitter 160 and waveguides 170, 180 of the first chip 100 can maintain the TE polarization of the signal. In this way, the first modulated signal can leave the first modulated signal port TEO1 with the help of TE polarization, and the second modulated signal can also leave the second modulated signal port TEO2 with the help of TE polarization.

[0026] The second chip 200 may include a first optical port 210 (e.g., TEI1, TEI2, TPO), a polarization rotation and combining (PRC) element 220, and a second optical port 230 (e.g., PL1, PL2, TPI, DPO). Typically, the first optical port 210 is coupled to the optical port 150 of the first chip 100, and the second optical port 230 is coupled to the optical fiber array 300.

[0027] As shown in the figure, the first modulation signal waveguide 240 can couple the first modulation signal port TEI1 to the PRC element 220, and the second modulation signal waveguide 250 can couple the second modulation signal port TEI2 to the PRC element 220. In addition, the first modulation signal port TEI1 of the second chip 200 can be coupled to the first modulation signal port TEO1 of the first chip 100. In this way, the first modulation signal waveguide 240 can guide the first modulation signal leaving the first chip 100 to the PRC element 220 of the second chip 200. Similarly, the second modulation signal port TEI2 of the second chip 200 can be coupled to the second modulation signal port TEO2 of the first chip 100. In this way, the second modulation signal waveguide 250 can guide the second modulation signal leaving the first chip 100 to the PRC element 220.

[0028] The second chip 200 may further include a multi-polarization signal waveguide 260 that couples the PRC element 220 to the multi-polarization or dual-polarization signal port DPO. The second chip 200 may also include a transparent waveguide 270 that couples the unmodulated signal port TPI to the unmodulated signal port TPO of the second chip 200. As shown in the figure, the unmodulated signal port TPO can be coupled to the signal input port IN of the first chip 100. In this way, the unmodulated signal generated by a laser or other signal source can be provided to the unmodulated signal port TPI of the second chip 200 via the optical fiber of the optical fiber array 300, and the transparent waveguide 270 can guide the unmodulated signal through the second chip 200 and to the first chip 100 via the unmodulated signal port TPO.

[0029] As further shown, the second chip 200 can include a passive loop waveguide 280 that couples the first passive loop port PL1 to the second passive loop port PL2. As explained in more detail below, the passive loop ports PL1, PL2, and the passive loop waveguide 280 can help properly align the optical fibers 310 of the optical fiber array 300 with the optical ports 230.

[0030] Due to the above-mentioned waveguide, the first modulation signal and the second modulation signal of the first chip 100 are guided to the PRC element 220. The PRC element 220 can rotate the polarization of one of the received modulation signals (e.g., the first modulation signal) and can combine the rotated signal with the other modulation signal (e.g., the second modulation signal) into a combined modulation signal having multiple polarizations. The multi-polarization signal waveguide 260 can guide the combined modulation signal from the PRC element 220 to the multi-polarization signal port DPO. In various embodiments, the first chip 100 can transmit the first modulation signal and the second modulation signal having TE polarization. The PRC element 220 can rotate the TE polarization of one of the signals by 90°, so that the rotated signal has TM polarization. In this way, the PRC element 220 can provide a combined modulation signal having dual polarization, which includes data carried by the TE polarization signal of the combined modulation signal and data carried by the TM polarization signal.

[0031] Unlike III-V semiconductor chip materials, silicon is very suitable for TE and TM signals. In particular, silicon-on-insulator waveguides provide very good confinement for TE and TM signals. In addition, the silicon chip structure can realize polarization rotation and signal combining functions in a very compact footprint. Therefore, the first chip 100 and the second chip 200 of the optical communication system 10 can fully utilize the strength of their corresponding semiconductor chip materials. In other words, the optical communication system 10 can combine the strength of InP or other III-VI materials (e.g., efficient modulation and amplification) with the strength of SiP (e.g., low-loss waveguides, compact structure and polarization processing).

[0032] As shown, the optical port 150 of the first chip 100 can be coupled to the first optical port 210 of the second chip 200 via a first epoxy 400. Similarly, the second optical port 230 of the second chip 200 can be coupled to the optical fiber 310 of the optical fiber array 300 via a second epoxy 500. In some embodiments, one or more end faces of the optical ports 150, 210, 230 can be coated with an anti-reflection coating. The anti-reflection coating can have a refractive index that matches the refractive index of the epoxy 400, 500 that is bonded to the end faces of the corresponding optical ports 150, 210, 230. In some embodiments, the refractive index of the epoxy 400 and the epoxy 500 matches the refractive index of the waveguide mode of the second chip 200. In such embodiments, the end faces of the optical ports 210, 230 of the second chip 200 can be uncoated, and the end face of the optical port 150 of the first chip 100 can be coated with an anti-reflection coating that matches the refractive index of the epoxy 400. In some embodiments, the epoxy 500 on the fiber side of the second chip 200 may be different from the epoxy 400 on the first chip side of the second chip.

[0033] As described above, the second chip 200 may include a passive loop waveguide 280 between the optical ports PL1 and PL2, a transmission waveguide 270 coupled to the optical port TPI, and a multi-polarization signal waveguide 260 coupled to the multi-polarization signal port DPO. Furthermore, the optical ports PL1, PL2, TPI, and DPO are coupled to corresponding optical fibers 310 of the optical fiber array 300. In various embodiments, the spacing between the optical fibers 310 of the optical fiber array 300 matches the spacing between the optical ports PL1, TP1, DPO, and PL2 of the second chip 200. Similarly, the spacing between the optical ports TEI1, TEI2, and TPO of the second chip 200 matches the spacing between the optical ports TEO1, TEO2, and IN of the first chip 100.

[0034] To increase tolerance to misalignment, each of the optical port 150 of the first chip and the optical ports 210, 230 of the second chip 200 can include a spot size converter that expands the waveguide mode of the corresponding end face. In particular, the spot size converter for the optical port 230 of the second chip facing the fiber can expand the optical mode of the optical port 230 to match the fiber mode of the attached optical fiber 310. Similarly, the spot size converter for the optical port 210 facing the first chip can expand the optical mode to the optical mode of the optical port 150 of the first chip 100. In various embodiments, the spot size converter for the optical port 210 facing the first chip can expand fewer optical modes than the spot size converter for the optical port 230 facing the fiber.

[0035] To align the fiber array 300 with the optical ports 230, light can be injected into the optical fibers 310 corresponding to the optical port PL1. The relative positions of the second chip 200 and the fiber array 300 can then be adjusted to maximize the coupling of light applied to the optical port PL1 to the optical port PL2 via the passive loop waveguide 280. The optical fibers 310 corresponding to the optical port PL2 can be coupled to a photodetector or other sensor to monitor the coupling of light through the passive loop waveguide 280. As described above, the spacing of the optical ports 230 of the second chip 200 matches the spacing of the optical fibers 310 of the fiber array 300. Therefore, properly aligning the optical fibers 310 with the optical ports PL1 and PL2 through the alignment process described above ensures that the optical ports TP1 and DPO are also properly aligned with the corresponding optical fibers 310 of the fiber array 300. After proper alignment is achieved, epoxy 500 can be applied to attach and maintain proper alignment between the fiber array 300 and the second chip 200.

[0036] After the optical fiber array 300 is attached to the second chip 200, the optical port 150 of the first chip 100 can be aligned and coupled to the optical port 210 of the second chip. This alignment can be achieved actively based on the light exiting the optical port 150, or passively based on a fiducial or through flip-chip bonding technology. The remaining gap between the first chip 100 and the second chip can then be filled with epoxy 400.

[0037] The second chip 200 is described above and depicted in the accompanying drawings as part of the optical transmitter 20. However, the second chip 200 may also be adapted for use in an optical receiver. In particular, the optical port 230 of the second chip 200 may serve as an input port for the optical receiver. In such use, the PRC element 220 may split a TM-polarized signal from a TE-polarized signal for a dual-polarized signal. The PRC element 220 may further rotate the polarization of the TM-polarized signal to provide two TE-polarized signals at the optical port 210. In such a receiver implementation, the path through the optical port TPI may be used to allow local oscillator light to pass through the second chip 200 to one or more balanced receiver pairs of the first chip 100, which are configured to perform coherent reception using the received local oscillator signal.

[0038] exist Figures 2 to 5C Variations of the optical communication system 10 are described in . In particular, Figure 2 The optical communication system 11 is shown including an optical transmitter 21 coupled to an optical fiber array 301. Similar to the optical transmitter 20, the optical transmitter 21 may include a first chip 101 and a second chip 201 coupled to the optical fiber array 301. Figure 2 The first chip 101 and the second chip 201 can be similar to Figure 1 The first chip 100 and the second chip 200 are implemented. Figure 1 Similar to the first chip 100, the first chip 101 includes optical ports TEO1, TEO2 along the side of the first chip 101 facing the second chip. Figure 1 Unlike the first chip 100, the first chip 101 includes a signal input port IN along the other side of the first chip 101 (for example, a side opposite to or at a 90° angle to the side facing the second chip). By positioning the signal input port IN along a side other than the side facing the second chip, the unmodulated signal can be provided directly to the first chip 101 without first passing through the second chip 201. In this way, the second chip 201 can be implemented in a manner similar to the second chip 200, but may lack the transparent waveguide 270 and the associated optical ports TPI, TPO of the second chip 200. Similarly, the optical fiber array 301 connected to the second chip 201 may lack the optical fiber 310 of the optical fiber array 300 associated with the optical port TPI of the second chip 200.

[0039] Figure 3 The optical communication system 12 is shown including the optical transmitter 22 coupled to the optical fiber array 302. Similar to the optical transmitter 20, the optical transmitter 22 may include a first chip 102 and a second chip 202 coupled to the optical fiber array 302. Figure 3The first chip 102 and the second chip 202 may be similar to Figure 1 The passive loop waveguide 280 and the associated optical ports PL1 and PL2 of the second chip 200 may be missing. Similarly, the optical fiber array 302 attached to the second chip 202 may lack the optical fibers 310 of the optical fiber array 300 associated with the optical ports PL1 and PL2 of the second chip 200.

[0040] Figure 4 The optical communication system 13 is shown including an optical transmitter 23 coupled to an optical fiber array 303. Similar to the optical transmitter 20, the optical transmitter 23 may include a first chip 103 and a second chip 203 coupled to the optical fiber array 303. Figure 4 The first chip 103 and the second chip 203 can be similar to Figure 1 The first chip 100 and the second chip 200 are implemented. Figure 1 Similar to the first chip 100, the first chip 103 may include optical ports TEO1, TEO2 along the side of the first chip 103 facing the second chip. Figure 1 Unlike the first chip 100, the first chip 103 includes a signal input port IN along the other side of the first chip 103 (for example, a side opposite to or at a 90° angle to the side facing the second chip). By positioning the signal input port IN along a side other than the side facing the second chip, the unmodulated signal can be provided directly to the first chip 103 without first passing through the second chip 203. In this way, the second chip 203 can be implemented in a manner similar to the second chip 200, but may lack the transparent waveguide 270 and the associated optical ports TPI, TPO of the second chip 200. Similarly, the optical fiber array 303 connected to the second chip 203 may lack the optical fiber 310 of the optical fiber array 300 associated with the optical port TPI of the second chip 200.

[0041] Furthermore, the second chip 203 may lack the passive loop waveguide 280 and associated optical ports PL1, PL2 of the second chip 200. Thus, the fiber array 303 attached to the second chip 203 may lack the optical fibers 310 of the fiber array 300 associated with the optical ports PL1, PL2 of the second chip 200.

[0042] Figures 5A to 5C The optical communication system 14 is depicted including the optical transmitter 24 coupled to the optical fiber array 300. Similar to the optical transmitter 20, the optical transmitter 24 may include a first chip 104 and a second chip 204 coupled to the optical fiber array 300. Figures 5A to 5CThe first chip 104 and the second chip 204 can be similar to Figure 1 However, unlike the optical transmitter 20, the second chip 204 can be stacked on the first chip 104, and vice versa. Figures 5A to 5C As shown in Figure 5A A bottom view of the optical communication system 14 is provided. Figure 5B A side view of the optical communication system 14 is provided, and Figure 5C A radial view of the optical communication system 14 is provided.

[0043] As shown, first chip 104 may include a first chip top side 104T, a first chip bottom side 104B opposite to first chip top side 104T, and a first chip lateral side 104L between first chip top side 104T and first chip lateral side 104L. Similarly, second chip 204 may include a second chip top side 204T, a second chip bottom side 204B opposite to second chip top side 204T, and a second chip lateral side 204L between second chip top side 204T and second chip lateral side 204L.

[0044] like Figure 5B As best shown in FIG. 1 , the second chip bottom side 204B can be layered such that the second chip top side 204B includes a top surface 205T, a bottom surface 205B, and a side surface 205L between the top surface 205T and the bottom surface 205B. The optical ports 210 of the second chip 204 (e.g., optical ports TEI1, TEI2, TPO) can be positioned between the top surface 205T and the bottom surface 205B along the side surface 205L. As a result of this positioning, the second chip 204 can be positioned above the first chip 104 such that the bottom surface 205B of the second chip bottom side 204B rests on and / or is coupled to the first chip top side 104T. Furthermore, this positioning can vertically align the optical ports 150 of the first chip 104 (e.g., optical ports TEO1, TEO2, IN) with the ports 210 of the second chip 204.

[0045] Figures 5A to 5C An embodiment is depicted in which the surface of the second chip 204 is layered. However, the optical emitter 24 can be implemented with a layered surface of the first chip 104 instead of the surface of the second chip 204. Similarly, in some embodiments, both the surface of the first chip 104 and the surface of the second chip 204 can be layered.

[0046] also, Figures 5A to 5C The optical transmitter 24 generally depicts Figure 1 However, Figures 5A to 5C The stacking configuration can achieve Figures 2 to 4 Optical transmitters 21, 22, 23.

[0047] Furthermore, as described above, the second chip 200 may be a part of an optical receiver, and may be used to branch and rotate a TM polarization signal from a dual-polarization signal including a TM polarization signal and a TE polarization signal. Figures 2 to 5C The second chips 201 , 202 , 203 , and 204 may also be part of an optical receiver and may be used to split and rotate the TM polarization signal from the dual-polarization signal including the TM polarization signal and the TE polarization signal.

[0048] Now refer to Figure 6 , shows an alignment device 600, which can be used to help Figure 3 The optical port 230 of the second chip 202 is aligned with the optical fiber 310 of the optical fiber array 302. The alignment device 600 can also be used to align the optical fiber array 303 to the optical fiber 310 of the optical fiber array 302. Figure 4 The multi-polarization signal port DPO of the second chip 203 is shown only. Figure 3 The process is similar to the second chip 202. Figure 4 The second chip 203.

[0049] Because the second chips 202 and 203 may lack the passive loop waveguide 280, the alignment process discussed above with respect to the optical transmitter 20 may not be suitable. To align the fiber array 302 with the optical port 230 of the second chip 202, an alignment device 600 can be coupled to the optical port 210 of the second chip 202. Specifically, the alignment device 600 can include two laser outputs LASER1 and LASER2 aligned with the optical ports TEI1 and TEI2 of the second chip 202. The laser outputs LASER1 and LASER2 can inject light into the optical ports TEI1 and TEI2. The second chip 202 can direct this light to the multi-polarization signal port DPO. The relative position of the second chip 200 and the fiber array 300 can then be adjusted to maximize the coupling of light applied to the multi-polarization signal port DPO. The optical fiber 310 corresponding to the multi-polarization signal port DPO can be coupled to a photodetector or other sensor to monitor the coupling of light to the multi-polarization signal port DPO. In various embodiments, the spacing of the optical ports 230 of the second chip 202 matches the spacing of the optical fibers 310 of the fiber array 302. Therefore, properly aligning the optical fibers 310 with the multi-polarization signal ports DPO via the alignment process described above ensures that the optical ports TP1 are also properly aligned with the corresponding optical fibers 310 of the fiber array 300. After proper alignment is achieved, epoxy 500 can be applied to attach and maintain proper alignment between the fiber array 302 and the second chip 202.

[0050] After the optical fiber array 302 is attached to the second chip 202, the alignment device 600 can be removed and the optical port 150 of the first chip 102 can be aligned and coupled to the optical port 210 of the second chip 202. This alignment can be achieved actively based on the light exiting the optical port 150, or passively based on a fiducial or through flip-chip bonding technology. The remaining gap between the first chip 102 and the second chip 202 can then be filled with epoxy 400.

[0051] Now refer to Figure 7 , shows an alignment device 601 that can be used to help align the optical port 230 of the second chip 202 with the optical fiber 310 of the optical fiber array 302. Since the second chip 202 may lack the passive loop waveguide 280, the alignment process discussed above with respect to the optical transmitter 20 may not be suitable.

[0052] To align the fiber array 302 with the optical port 230, an alignment device 601 can be coupled to the optical port 210 of the second chip 202. Specifically, the alignment device 601 can include two laser outputs LASER1 and LASER2 aligned with the optical ports TEI1 and TEI2 of the second chip 202, and an optical port PD coupled to a photodetector of the alignment device 601 of another device. The laser outputs LASER1 and LASER2 can inject light into the optical ports TEI1 and TEI2. The second chip 202 can direct this light to the multi-polarization signal port DPO. Furthermore, the optical fiber 310 associated with the optical port TPI can inject light into the optical port TPI for coupling into the optical port PD and detection by the alignment device 601 or a photodetector of another device. Alignment can be performed by first maximizing the coupling of the optical port PD to fix the lateral position of the second chip 202 relative to the fiber array 300. In subsequent steps, the rotational positioning of the second chip 202 with respect to the optical fiber array 300 can involve maximizing the coupling of light applied to the multi-polarization signal port DPO via the laser outputs LASER1 and LASER2 by optimizing the rotation of the optical fiber array 300 about the axis of the optical fiber 310 associated with the optical port TPI. To this end, the optical fiber 310 corresponding to the multi-polarization signal port DPO can be coupled to a photodetector or other sensor to monitor the coupling of light to the multi-polarization signal port DPO. After proper alignment is achieved, epoxy 500 can be applied to attach and maintain proper alignment between the optical fiber array 302 and the second chip 202.

[0053] After the optical fiber array 302 is attached to the second chip 202, the alignment device 601 can be removed and the optical port 150 of the first chip 102 can be aligned and coupled to the optical port 210 of the second chip 202. This alignment can be achieved actively based on the light exiting the optical port 150, or passively based on a fiducial or through flip-chip bonding technology. The remaining gap between the first chip 102 and the second chip 202 can then be filled with epoxy 400.

[0054] This disclosure includes references to certain examples, however, those skilled in the art will understand that various changes may be made and equivalents may be substituted without departing from the scope of this disclosure. In addition, modifications may be made to the disclosed examples without departing from the scope of this disclosure. Therefore, it is intended that this disclosure is not limited to the disclosed examples, but rather that this disclosure includes all examples that fall within the scope of the appended claims.

Claims

1. An optical device comprising: A first chip includes a first polarization signal optical port, a second polarization signal optical port, and one or more optical elements coupled to the first polarization signal optical port and the second polarization signal optical port; as well as a second chip comprising a first polarized signal optical port coupled to the first polarized signal optical port of the first chip, a second polarized signal optical port coupled to the second polarized signal optical port of the first chip, a multi-polarized signal optical port, and a polarization rotation and combination element coupling the first polarized signal optical port and the second polarized signal optical port of the second chip to the multi-polarized signal optical port of the second chip; Wherein, the first chip comprises a first semiconductor chip material; and The second chip includes a second semiconductor chip material different from that of the first semiconductor chip.

2. The optical device according to claim 1, wherein: The first semiconductor chip material comprises a III-V semiconductor material; and The second semiconductor chip material includes silicon.

3. The optical device according to claim 2, wherein The III-V semiconductor material includes indium phosphide (InP).

4. The optical device according to claim 2, wherein The III-V semiconductor material includes gallium arsenide (GaAs).

5. The optical device according to claim 1, wherein The one or more optical elements of the first chip include one or more modulators, wherein the modulators are configured to: providing a first polarized optical signal having a first polarization to a first polarized optical signal port of the first chip; as well as A second polarized optical signal having a second polarization that is the same as the first polarization is provided to a second polarized optical signal port of the first chip.

6. The optical device according to claim 5, wherein The polarization rotation and combining elements of the second chip are configured as follows: rotating the first polarized optical signal received from the first chip into a third polarized optical signal having a third polarization different from the second polarization of the second polarized optical signal; combining the third polarized optical signal with the second polarized optical signal; and The combined signal is provided to the multi-polarization signal optical port.

7. The optical device according to claim 1, wherein The one or more optical elements of the first chip include one or more modulators, wherein the modulators are configured to: providing a first transverse electric polarization signal to a first polarization optical signal port of the first chip; as well as A second transverse electric polarization signal is provided to a second polarization optical signal port of the first chip.

8. The optical device according to claim 7, wherein The polarization rotation and combining elements of the second chip are configured as follows: rotating the first transverse electric polarization signal into a transverse magnetic polarization signal; combining the transverse magnetic polarization signal with the second transverse electric polarization signal to obtain a combined signal comprising the transverse magnetic polarization signal and the second transverse electric polarization signal; and The combined signal is provided to the multi-polarization signal optical port.

9. The optical device according to claim 1, wherein The polarization rotation and combining elements of the second chip are configured as follows: receiving a multi-polarized optical signal from a multi-polarized signal optical port of the second chip, wherein the multi-polarized optical signal includes a first polarized optical signal having a first polarization and a second polarized optical signal having a second polarization, and wherein the first polarization is different from the second polarization; rotating the first polarized optical signal into a rotated first polarized optical signal having a third polarization, such that the rotated first polarized optical signal and the second polarized optical signal have the same polarization; providing the rotated first polarized optical signal to the first chip via a first polarized optical signal port of the second chip; and The second polarized optical signal is provided to the first chip via a second polarized optical signal port of the second chip.

10. The optical device according to claim 1, wherein The polarization rotation and combining elements of the second chip are configured as follows: receiving a dual-polarized optical signal from the multi-polarized signal optical port of the second chip, wherein the dual-polarized optical signal includes a first transverse electric polarization signal and a second transverse magnetic polarization signal; rotating the second transverse magnetic polarization signal into a second transverse electric polarization signal; providing the first transverse electric polarization signal to the first chip via a first polarization optical signal port of the second chip; and The second transverse electric polarization signal is provided to the first chip via a second polarization optical signal port of the second chip.

11. The optical device according to claim 1, wherein The second chip includes: a first passive loop optical port; a second passive loop optical port; and A passive loop waveguide couples the first passive loop optical port and the second passive loop optical port.

12. The optical device according to claim 1, wherein The second chip includes: a first transparent optical port along a first lateral side of the second chip; a second transparent optical port along a second lateral side of the second chip; and The transparent waveguide couples the first transparent optical port and the second transparent optical port.

13. The optical device according to claim 1, wherein The first chip includes an input optical port coupled to a first transparent optical port of the second chip.

14. The optical device according to claim 13, wherein: The first chip and the second chip are part of an optical transmitter; and The one or more optical elements of the first chip include one or more modulators configured to modulate unmodulated signals received via the input optical port of the first chip and the first transparent optical port of the second chip.

15. The optical device of claim 13, wherein: The first chip and the second chip are part of an optical receiver; and The one or more optical elements of the first chip include one or more balanced receiver pairs configured to perform coherent reception using a local oscillator signal received via the input optical port of the first chip and the first pass-through optical port of the second chip.

16. The optical device of claim 1, comprising an optical fiber array of one or more optical fibers coupled to the second chip.

17. The optical device of claim 16, comprising epoxy attaching the optical fiber array to the second chip, wherein The refractive index of the epoxy resin matches the refractive index of the second chip.

18. The optical device of claim 1, comprising an epoxy attaching the first chip to the second chip, wherein The refractive index of the epoxy resin matches the refractive index of the second chip.

19. The optical device according to claim 18, wherein One or more end faces of the first polarization optical signal port and the second polarization optical signal port are coated with an anti-reflection coating having a refractive index matching that of the epoxy resin.

20. The optical device of claim 1, wherein: The first chip is stacked on the second chip; and The first chip and / or the second chip may have respective chip-facing optical ports positioned along side surfaces between layered surfaces of the respective first chip and / or the second chip.

Images