A light and small three-axis multiplexing photon chip gyroscope

Abstract

The present application belongs to the field of integrated optics and optical fiber sensing technology, and particularly relates to a light and small three-axis multiplexing photonic chip gyroscope. The gyroscope is composed of a silicon-based hybrid integrated chip, a six-channel polarization maintaining optical fiber array, a fiber ring I, a fiber ring II, a fiber ring III, a PZT modulator I, a PZT modulator II, a PZT modulator III and a control circuit. The gyroscope is monolithically integrated with discrete optical path devices and is integrally packaged, so that the optical path size and cost are greatly reduced, the optical fiber interconnection is reduced, the assembly process complexity is obviously reduced, and the long-term reliability of the gyroscope performance is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of integrated optics and fiber optic sensing technology, and specifically relates to a lightweight, miniature, three-axis multiplexed photonic chip gyroscope. Background Technology

[0002] Inertial sensors based on fiber optic gyroscopes are key components in aviation, aerospace, maritime, and land navigation systems, and are widely used in the military field. Each inertial measurement unit or inertial navigation system requires at least one three-axis gyroscope to sense the rotational angular rate in three orthogonal directions. Traditional three-axis fiber optic gyroscope implementations often use three independent optical paths to measure the three orthogonal sensing axes of the gyroscope. This significantly increases the number of optical path components and the size of the gyroscope, while also increasing the complexity of processes such as splicing and fiber optic cable winding between components, which is not conducive to reducing the cost and size of the gyroscope. In addition, while three-axis fiber optic gyroscopes can currently be partially integrated using PLC splitters to achieve functions such as one-to-three or two-to-two beam splitters, they cannot achieve the same effect as polarizers and cannot meet the overall on-chip integration requirements of three-axis gyroscopes. Therefore, traditional implementation schemes are increasingly unable to meet the requirements of inertial navigation systems for miniaturization, lightweighting, and low cost of fiber optic gyroscopes. Summary of the Invention

[0003] The technical problem solved by the present invention: In view of the shortcomings of the prior art, the present invention provides a lightweight and compact three-axis multiplexed photonic chip gyroscope.

[0004] The technical solution of the present invention:

[0005] A lightweight, miniature three-axis multiplexed photonic chip gyroscope comprises a silicon-based hybrid integrated chip 1, a six-channel polarization-maintaining fiber array 2, fiber ring I 3, fiber ring II 4, fiber ring III 5, PZT modulator I 6, PZT modulator II 7, PZT modulator III 8, and a control circuit 9.

[0006] A six-channel polarization-maintaining fiber array 2 is glued to the end face of a silicon-based hybrid integrated chip 1;

[0007] The two pigtails of fiber ring I3, the two pigtails of fiber ring II4, and the two pigtails of fiber ring III5 serve as the six channels of the six-channel polarization-maintaining fiber array 2.

[0008] One of the pigtails of the optical fiber ring I3 is wound around the PZT modulator I6;

[0009] One of the pigtails of the optical fiber ring II4 is wound around the PZT modulator II7.

[0010] One of the pigtails of the optical fiber ring Ⅲ5 is wound around the PZT modulator Ⅲ8.

[0011] Furthermore, fiber rings I3, II4, and III5 are orthogonally placed on the three sensitive axes X, Y, and Z of the three-axis multiplexed photonic chip gyroscope;

[0012] The control circuit 9 is connected to the silicon-based hybrid integrated chip 1, PZT modulator I 6, PZT modulator II 7, and PZT modulator III 8, respectively.

[0013] Furthermore,

[0014] The silicon-based hybrid integrated chip 1 includes: an SLD chip 1-1, a mode converter 1-2, a one-to-three beam splitter 1-3, a cross structure 1-4, a two-to-two beam splitter I 1-5, a two-to-two beam splitter II 1-6, a two-to-two beam splitter III 1-7, a stray light absorber I 1-8, a stray light absorber II 1-9, a stray light absorber III 1-10, a polarizer I 1-11, a polarizer II 1-12, a polarizer III 1-13, a beam splitter I 1-14, and a beam splitter II 1. -15, Beam splitter Ⅲ1-16, Fiber-to-waveguide coupler Ⅰ1-17, Fiber-to-waveguide coupler Ⅱ1-18, Fiber-to-waveguide coupler Ⅲ1-19, Fiber-to-waveguide coupler Ⅳ1-20, Fiber-to-waveguide coupler Ⅴ1-21, Fiber-to-waveguide coupler Ⅵ1-22, End-face coupler Ⅰ1-23, End-face coupler Ⅱ1-24, End-face coupler Ⅲ1-25, Detector Ⅰ1-26, Detector Ⅱ1-27, Detector Ⅲ1-28;

[0015] The SLD chip 1-1 is connected to the input terminal of the 1-to-3 beam splitter 1-3 via the mode converter I1-2; the three output terminals of the 1-to-3 beam splitter 1-3 are respectively connected to the first ports of the 2-to-2 beam splitter I1-5, 2-to-2 beam splitter II1-6, and 2-to-2 beam splitter III1-7; the second ports of the 2-to-2 beam splitter I1-5, 2-to-2 beam splitter II1-6, and 2-to-2 beam splitter III1-7 are respectively connected to the end-face coupler I1-23, end-face coupler II1-24, and end-face coupler III1-7. Coupler Ⅲ1-25 is connected to detector Ⅰ1-26, detector Ⅱ1-27, and detector Ⅲ1-28 respectively; the third ports of beam splitters Ⅰ1-5, Ⅱ1-6, and Ⅲ1-7 are connected to stray light absorbers Ⅰ1-8, Ⅱ1-9, and Ⅲ1-10 respectively; the fourth ports of beam splitters Ⅰ1-5, Ⅱ1-6, and Ⅲ1-7 are connected to polarizer Ⅰ1-11. The input terminals of polarizers II (1-12) and III (1-13) are connected; the output terminals of polarizers I (1-11), II (1-12), and III (1-13) are connected to the input terminals of beam splitters I (1-14), II (1-15), and III (1-16), respectively; the output terminals of beam splitters I (1-14), II (1-15), and III (1-16) are connected through fiber-to-waveguide coupler I (1-17) and fiber-to-waveguide coupler. Components II1-18, fiber-to-waveguide coupler III1-19, fiber-to-waveguide coupler IV1-20, fiber-to-waveguide coupler V1-21, and fiber-to-waveguide coupler VI1-22 are respectively connected to the first channel 2-1, the second channel 2-2, the third channel 2-3, the fourth channel 2-4, the fifth channel 2-5, and the sixth channel 2-6 of the six-channel polarization-maintaining fiber array.

[0016] Furthermore,

[0017] The passive components of the silicon-based hybrid integrated chip 1 include: mode converter 1-2, one-to-three beam splitter 1-3, cross structure 1-4, two-to-two beam splitter I 1-5, two-to-two beam splitter II 1-6, two-to-two beam splitter III 1-7, stray light absorber I 1-8, stray light absorber II 1-9, stray light absorber III 1-10, polarizer I 1-11, polarizer II 1-12, polarizer III 1-13, and beam splitter. I1-14, Beam splitter II1-15, Beam splitter III1-16, Fiber-to-waveguide coupler I1-17, Fiber-to-waveguide coupler II1-18, Fiber-to-waveguide coupler III1-19, Fiber-to-waveguide coupler IV1-20, Fiber-to-waveguide coupler V1-21, Fiber-to-waveguide coupler VI1-22, End-face coupler I1-23, End-face coupler II1-24, End-face coupler III1-25;

[0018] The passive device is integrated on a single silicon-based SiN chip;

[0019] SLD chip 1-1, detector I 1-26, detector II 1-27, and detector III 1-28 are integrated with a monolithic silicon-based SiN chip through end-face bonding to realize silicon-based hybrid integrated chip 1.

[0020] Furthermore,

[0021] The TEC temperature control chip in the control circuit 9 performs overall temperature control on the silicon-based hybrid integrated chip 1.

[0022] The detector control module of the control circuit 9 receives the optical signal output from any detector output terminal and feeds it back to the SLD chip 1-1 for optical power adjustment and compensation, so that the optical power of the detector remains constant during the rotation of the gyroscope.

[0023] Furthermore,

[0024] The one-to-three beam splitters 1-3 adopt a 1×3 multimode interference (MMI) beam splitter structure;

[0025] The two-to-two beam splitters I1-5, II1-6, and III1-7 adopt the same 2×2 multimode interference (MMI) beam splitter structure to achieve a uniform beam splitting ratio and are connected to a stray light absorber to absorb stray light with inherent losses.

[0026] Furthermore,

[0027] The beam splitters I1-14, II1-15, and III1-16 all adopt the same 1×2 Y-branch structure and have an operating wavelength range of 810nm~890nm.

[0028] The cross structure 1-4 is formed by the perpendicular intersection of the waveguide of the first output port of the one-to-three beam splitter 1-3 and the waveguide of the second port of the two-to-two beam splitter II 1-6.

[0029] Furthermore,

[0030] The polarizers I1-11, II1-12, and III1-13 all adopt the same large waveguide aspect ratio cascaded structure.

[0031] The fiber-to-waveguide couplers I1-17, II1-18, III1-19, IV1-20, V1-21, and VI1-22 all employ identical inverted conical structures to achieve mode field matching and are distributed in parallel at equal intervals on the same end face of the chip. Furthermore, the spacing between two adjacent fiber-to-waveguide couplers is equal to the spacing between two channels of the six-channel polarization-maintaining fiber array, and the spacing between adjacent fiber-to-waveguide couplers is either 250 μm or 500 μm.

[0032] Furthermore,

[0033] The end-face couplers I1-23, II1-24, and III1-25 all adopt the same linear tapered waveguide structure;

[0034] The stray light absorbers I1-8, II1-9, and III1-10 have identical structures, and are formed by deep etching to create wide waveguide partitions, which are then filled with light-absorbing material.

[0035] Furthermore,

[0036] The PZT modulators I6, II7, and III8 are respectively placed at the center of fiber ring I3, fiber ring II4, and fiber ring III5.

[0037] This invention proposes a lightweight, miniaturized three-axis multiplexed photonic chip gyroscope, which utilizes optical path multiplexing technology and silicon-based hybrid photonic integrated chips to achieve full on-chip integration of the three-axis integrated fiber optic gyroscope functional devices. The gyroscope's discrete optical path components are monolithically integrated and packaged, significantly reducing optical path size and cost, minimizing fiber optic interconnections, and significantly reducing assembly process complexity, effectively improving the long-term reliability of the gyroscope's performance. Furthermore, leveraging mature silicon photonic CMOS technology, low-cost, large-scale mass production of compact three-axis photonic integrated chip fiber optic gyroscopes can be achieved, meeting the future inertial navigation system's demands for miniaturization, lightweighting, and cost reduction of three-axis fiber optic gyroscopes. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the lightweight, miniature, three-axis multiplexed photonic chip gyroscope of the present invention;

[0039] Figure 2 It is a SiN waveguide structure;

[0040] Figure 3 (a) 1×3 MMI beam splitter structure; (b) 2×2 MMI coupler structure;

[0041] Figure 4 (a) Simulation diagram of the optical field of a 1×3 MMI; (b) Simulation diagram of the optical field of a 2×2 MMI;

[0042] Figure 5 Top view of a fiber-to-waveguide coupler;

[0043] Figure 6 This is a schematic diagram of the stray light absorption structure. Detailed Implementation

[0044] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail and completely below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] The present invention will now be described in further detail with reference to the accompanying drawings:

[0046] See Figure 1 The present invention discloses a lightweight, miniature three-axis multiplexed photonic chip gyroscope, primarily composed of a silicon-based hybrid integrated chip 1, a six-channel polarization-maintaining fiber array 2, fiber rings I, II, and III 5, PZT modulators I, II, and III 6, and a control circuit 9. One end of each of the fiber rings I, II, and III 5 is wound with PZT modulators II 7 and III 8, respectively. The six-channel polarization-maintaining fiber array 2 is efficiently coupled to the silicon-based hybrid photonic integrated chip 1. The control circuit 9 applies modulation signals to the PZT modulators, simultaneously powers the light source and temperature control module, and demodulates the optical signal output from the silicon-based hybrid integrated chip.

[0047] The silicon-based hybrid integrated chip includes: SLD chip 1-1, mode converter 1-2, one-to-three beam splitter 1-3, cross structure 1-4, two-to-two beam splitter I 1-5, two-to-two beam splitter II 1-6, two-to-two beam splitter III 1-7, stray light absorber I 1-8, stray light absorber II 1-9, stray light absorber III 1-10, polarizer I 1-11, polarizer II 1-12, polarizer III 1-13, beam splitter I 1-14, and beam splitter II 1. -15, Beam splitter Ⅲ1-16, Fiber-to-waveguide coupler Ⅰ1-17, Fiber-to-waveguide coupler Ⅱ1-18, Fiber-to-waveguide coupler Ⅲ1-19, Fiber-to-waveguide coupler Ⅳ1-20, Fiber-to-waveguide coupler Ⅴ1-21, Fiber-to-waveguide coupler Ⅵ1-22, End-face coupler Ⅰ1-23, End-face coupler Ⅱ1-24, End-face coupler Ⅲ1-25, Detector Ⅰ1-26, Detector Ⅱ1-27, Detector Ⅲ1-28.

[0048] The light emitted from SLD source 1-1 is split into three equal parts by mode converter 1-2 and beam splitter 1-3, respectively entering beam splitter I1-5, beam splitter II1-6, and beam splitter III1-7. The light entering beam splitter I1-5 is further split into two parts. One half is absorbed and depleted by stray light absorber I1-8, while the other half passes through polarizer I1-11, beam splitter I1-14, fiber-to-waveguide coupler I1-17, and fiber-to-waveguide coupler IV1-20, and then connects to the six-channel polarization-maintaining fiber array 2. The first channel 2-1 and the second channel 2-2 are efficiently coupled and connected to both ends of the fiber optic loop 5 of the first-axis gyroscope. The loop light passes through beam splitter I1-14 and polarizer I1-11 to reach the two-to-two beam splitter I1-5, and is then output to detector I1-26 with low loss through end-face coupler I1-23, forming the complete optical path of the first-axis gyroscope. The light entering the two-to-two beam splitter II1-6 is split into two parts. One half of the light is absorbed and depleted by stray light absorber II1-9, and the other half passes through polarizer II1-12 and beam splitter II1-15 through fiber-optic waveguide. The fiber-to-waveguide coupler II1-18 and the fiber-to-waveguide coupler V1-21 are efficiently coupled to the third channel 2-3 and the fourth channel 2-4 of the six-channel polarization-maintaining fiber array 2, and connected to both ends of the fiber loop 6 of the second-axis gyroscope. The loop light passes through the beam splitter II1-15 and the polarizer II1-12 to reach the two-to-two beam splitter II1-6, and is output to the detector II1-27 with low loss through the end-face coupler II1-24, forming the complete optical path of the second-axis gyroscope. The light entering the two-to-two beam splitter III1-7 is split into two parts, one half of which is absorbed by the stray light absorber III1. -10 absorption depletion, the other half of the light passes through polarizer Ⅲ1-13, beam splitter Ⅲ1-16, fiber-to-waveguide coupler Ⅲ1-19, and fiber-to-waveguide coupler Ⅵ1-22 to efficiently couple with the fifth channel 2-5 and the sixth channel 2-6 of the six-channel polarization-maintaining fiber array 2, and connects to both ends of the fiber loop 7 of the third-axis gyroscope. The loop light passes through beam splitter Ⅲ1-16, polarizer Ⅲ1-13 to reach the two-to-two beam splitter Ⅲ1-7, and is output to the detector Ⅲ1-28 with low loss through end-face coupler Ⅲ1-25, forming the complete optical path of the third-axis gyroscope.

[0049] In one implementation, one end of the fiber ring I3, fiber ring II4, and fiber ring III5 is wound with PZT modulator I6, PZT modulator II7, and PZT modulator III8, respectively, and they are orthogonally placed on the three sensitive axes X, Y, and Z of the three-axis multiplexed photonic chip fiber optic gyroscope.

[0050] In one implementation, the PZT modulator I6, PZT modulator II7, and PZT modulator III8 are placed at the center of fiber ring I3, fiber ring II4, and fiber ring III5, respectively, to reduce the gyroscope volume.

[0051] In one implementation, the 1×3 beam splitter adopts a symmetrical 1×3 MMI structure, and the 2×2 MMI structure is adopted for the 2×2 beam splitter I, 2×2 beam splitter II, and 2×2 beam splitter III. The inherent 3dB loss light can be transmitted to the chip end face for absorption and processing by utilizing the third output port of the 2×2 MMI beam splitter, thereby reducing on-chip stray light crosstalk.

[0052] To reduce device size, this embodiment of the invention utilizes a silicon-based SiN waveguide for optimized beam splitter design. (See [link]). Figure 2 , Figure 3 The SiN waveguide width is 950nm, and the center wavelength of the triaxial multiplexed photonic chip is 850nm. The designed 1×3 MMI structure parameters are: multimode interference region width 24μm, length 218μm, input / output tapered waveguide width 3μm, length 120μm, with TE0 mode insertion loss of -0.1dB and a splitting ratio of 1:1:1. The designed 2×2 MMI structure parameters are: multimode interference region width 10μm, length 242μm, input / output tapered waveguide width 3.5μm, length 200μm, TE0 mode insertion loss of -0.045dB, and a splitting ratio of 1:1. See [link to relevant documentation]. Figure 4 .

[0053] In one implementation, beam splitters I1-14, II1-15, and III1-16 adopt a 1×2 Y-branch structure with an operating wavelength range of 810nm to 890nm. The designed Y-branch structure takes into account fabrication feasibility, and its parameters are: branch spacing of 200nm, input tapered waveguide length of 180μm, output arm spacing of 250μm, bent waveguide length of 695μm, and bending radius of approximately 1000μm. At this configuration, the TE0 mode insertion loss is -0.051dB, and the splitting ratio is 1:1.

[0054] In one implementation, the cross structure 1-4 is formed by the waveguides of the first output port of the one-to-three beam splitter 1-3 and the waveguides of the second port of the two-to-two beam splitter II 1-6 arranged perpendicularly to ensure minimal coupling loss.

[0055] As one implementation method, the polarizer adopts a cascaded curved waveguide structure with a large aspect ratio. The main structural principle is as follows: by utilizing the birefringence of the large aspect ratio waveguide structure, the effective refractive indices of the TE0 and TM0 modes differ greatly, and the bending loss of the TE0 mode is much smaller than that of the TM0 mode. Through the cascaded curved waveguide structure, the TM0 mode light is almost completely attenuated and dissipated, while the TE0 mode light is transmitted with low loss, thereby achieving an ultra-high extinction ratio polarization of >80dB.

[0056] In one implementation, the fiber-to-waveguide couplers I1-17, II1-18, III1-19, IV1-20, V1-21, and VI1-22 all employ an inverted conical structure to achieve mode field matching. They are distributed in parallel at equal intervals on the same end face of the chip, and the spacing between the fiber-to-waveguide couplers is equal to the spacing between the two channels of the six-channel polarization-maintaining fiber array, with a value of 250μm or 500μm. The operating wavelength range of all of them is 810nm~890nm.

[0057] Taking fiber-waveguide coupler design as an example, see Figure 5 In the 850nm band, the mode field size of the 40μm / 80μm ​​ultra-fine diameter polarization-maintaining fiber is about 3.6μm. Mode matching can be achieved by optimizing the width of the inverted conical waveguide end face. With an inverted conical end face width of 200nm and an inverted conical length of 200μm, a coupling efficiency of 90.1% can be achieved.

[0058] In one implementation, the end-face couplers I1-23, II1-24, and III1-25 all employ linear tapered waveguides to increase the optical mode field.

[0059] In one implementation, stray light absorber I, stray light absorber II, and stray light absorber III have identical structures. They are achieved by using a deep etching process to form a wide waveguide partition, and then filling the partition with light-absorbing material. See [link to relevant documentation]. Figure 6 .

[0060] As one implementation method, the fiber optic ring uses ultra-fine diameter polarization-maintaining fiber with a cladding of 40μm and a coating of 80μm, which effectively reduces the size of the fiber optic ring and improves the accuracy of the gyroscope.

[0061] Specifically,

[0062] A lightweight, miniature three-axis multiplexed photonic chip gyroscope is mainly composed of a silicon-based hybrid integrated chip 1, a six-channel polarization-maintaining fiber array 2, fiber ring I 3, fiber ring II 4, fiber ring III 5, PZT modulator I 6, PZT modulator II 7, PZT modulator III 8, and a control circuit 9.

[0063] The silicon-based hybrid integrated chip includes: SLD chip 1-1, mode converter 1-2, one-to-three beam splitter 1-3, cross structure 1-4, two-to-two beam splitter I 1-5, two-to-two beam splitter II 1-6, two-to-two beam splitter III 1-7, stray light absorber I 1-8, stray light absorber II 1-9, stray light absorber III 1-10, polarizer I 1-11, polarizer II 1-12, polarizer III 1-13, beam splitter I 1-14, and beam splitter II 1. -15, Beam splitter Ⅲ1-16, Fiber-to-waveguide coupler Ⅰ1-17, Fiber-to-waveguide coupler Ⅱ1-18, Fiber-to-waveguide coupler Ⅲ1-19, Fiber-to-waveguide coupler Ⅳ1-20, Fiber-to-waveguide coupler Ⅴ1-21, Fiber-to-waveguide coupler Ⅵ1-22, End-face coupler Ⅰ1-23, End-face coupler Ⅱ1-24, End-face coupler Ⅲ1-25, Detector Ⅰ1-26, Detector Ⅱ1-27, Detector Ⅲ1-28.

[0064] The SLD chip 1-1 is connected to the input terminal of the 1-to-3 beam splitter 1-3 via the mode converter I1-2; the three output terminals of the 1-to-3 beam splitter 1-3 are respectively connected to the first ports of the 2-to-2 beam splitters I1-5, II1-6, and III1-7; the second ports of the 2-to-2 beam splitters I1-5, II1-6, and III1-7 are respectively connected to detectors I1-26, II1-27, and III1-28 via end-face couplers I1-23, II1-24, and III1-25; the third ports of the 2-to-2 beam splitters I1-5, II1-6, and III1-7 are respectively connected to stray light absorbers I1-8, II1-9, and III1-10, thus splitting the beams into two. The fourth ports of polarizers I1-5, II1-6, and III1-7 are connected to the inputs of polarizers I1-11, II1-12, and III1-13. The outputs of polarizers I1-11, II1-12, and III1-13 are connected to the first channel 2-1, the second channel 2-2, the third channel 2-3, the fourth channel 2-4, the fifth channel 2-5, and the sixth channel 2-6 of the six-channel polarization-maintaining fiber array, respectively, through fiber-to-waveguide couplers I1-17, II1-18, III1-19, IV1-20, V1-21, and VI1-22.

[0065] The passive optical components include: mode converters 1-2, 1-to-3 beam splitters 1-3, crossover structures 1-4, 2-to-2 beam splitters I 1-5, II 1-6, III 1-7, stray light absorbers I 1-8, II 1-9, III 1-10, polarizers I 1-11, II 1-12, III 1-13, beam splitters I 1-14, II 1-15, III 1-16, fiber-to-waveguide couplers I 1-17, II 1-18, and others. Optical fiber-waveguide coupler Ⅲ1-19, optical fiber-waveguide coupler Ⅳ1-20, optical fiber-waveguide coupler Ⅴ1-21, optical fiber-waveguide coupler Ⅵ1-22, end-face coupler Ⅰ1-23, end-face coupler Ⅱ1-24, and end-face coupler Ⅲ1-25 are integrated on a monolithic silicon-based SiN chip; SLD chip 1-1, detector Ⅰ1-26, detector Ⅱ1-27, and detector Ⅲ1-28 are integrated with the silicon-based SiN chip through end-face bonding to realize a silicon-based hybrid integrated chip; the TEC temperature control chip in control circuit 9 controls the overall temperature of the silicon-based hybrid integrated chip.

[0066] One end of each of the fiber optic rings I3, II4, and III5 is wound around a PZT piezoelectric ceramic modulator I6, a PZT modulator II7, and a PZT modulator III8, respectively. The fiber optic rings I3, II4, and III5 are orthogonally placed on the three sensitive axes X, Y, and Z of the three-axis photonic multiplexing chip fiber optic gyroscope.

[0067] 6. The detector control module of the control circuit 9 receives the change in the optical signal output from any detector output terminal and feeds it back to the SLD chip 1-1 for optical power adjustment and compensation, so that the detector optical power remains constant.

[0068] The 1×3 beam splitter 1-3 adopts a 1×3 multimode interference (MMI) beam splitter structure, while the 2×2 multimode interference (MMI) beam splitter I 1-5, 2×2 beam splitter II 1-6, and 2×2 beam splitter III 1-7 adopt the same 2×2 multimode interference (MMI) beam splitter structure to achieve a uniform beam splitting ratio and can be connected to a stray light absorber to absorb stray light with inherent losses.

[0069] Beam splitters I1-14, II1-15, and III1-16 all adopt the same 1×2 Y-branch structure, reducing the requirements for processing accuracy. The working wavelength range is 810nm~890nm.

[0070] The cross structure 1-4 is formed by the perpendicular intersection of the waveguide of the first output port of the one-to-three beam splitter 1-3 and the waveguide of the second port of the two-to-two beam splitter II 1-6, which effectively suppresses mode crosstalk of the transmitted light in the two waveguides.

[0071] The polarizers I1-11, II1-12, and III1-13 all adopt the same cascaded structure of curved waveguides with a large waveguide aspect ratio, which can achieve an ultra-high on-chip extinction ratio.

[0072] The fiber-to-waveguide couplers I1-17, II1-18, III1-19, IV1-20, V1-21, and VI1-22 all employ identical inverted conical structures to achieve mode field matching. They are distributed in parallel at equal intervals on the same end face of the chip, enabling rapid coupling alignment. Furthermore, the spacing between the fiber-to-waveguide couplers is equal to the spacing between two channels of the six-channel polarization-maintaining fiber array, and the spacing between adjacent fiber-to-waveguide couplers is either 250 μm or 500 μm.

[0073] The end-face couplers I1-23, II1-24, and III1-25 all adopt the same linear tapered waveguide structure.

[0074] The stray light absorbers I1-8, II1-9, and III1-10 have identical structures. They are formed by deep etching to create wide waveguide partitions, and light-absorbing materials are filled inside the partitions to reduce on-chip stray light crosstalk and improve gyroscope accuracy.

Claims

1. A lightweight, miniature, three-axis multiplexed photonic chip gyroscope, characterized in that, It consists of a silicon-based hybrid integrated chip (1), a six-channel polarization-maintaining fiber array (2), fiber ring I (3), fiber ring II (4), fiber ring III (5), PZT modulator I (6), PZT modulator II (7), PZT modulator III (8), and control circuit (9). A six-channel polarization-maintaining fiber array (2) is glued to the end face of a silicon-based hybrid integrated chip (1); The two pigtails of fiber ring I (3), the two pigtails of fiber ring II (4), and the two pigtails of fiber ring III (5) serve as the six channels of the six-channel polarization-maintaining fiber array (2). One of the pigtails of the optical fiber ring I (3) is wound around the PZT modulator I (6); One of the pigtails of the optical fiber ring II (4) is wound around the PZT modulator II (7); One of the pigtails of the optical fiber ring Ⅲ (5) is wound around the PZT modulator Ⅲ (8); Furthermore, fiber ring I (3), fiber ring II (4), and fiber ring III (5) are orthogonally placed on the three sensitive axes X, Y, and Z of the three-axis multiplexed photonic chip gyroscope; The control circuit (9) is connected to the silicon-based hybrid integrated chip (1), PZT modulator I (6), PZT modulator II (7), and PZT modulator III (8), respectively.

2. The lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 1, characterized in that, The silicon-based hybrid integrated circuit (1) includes: an SLD chip (1-1), a mode converter (1-2), a one-to-three beam splitter (1-3), a cross structure (1-4), a two-to-two beam splitter I (1-5), a two-to-two beam splitter II (1-6), a two-to-two beam splitter III (1-7), a stray light absorber I (1-8), a stray light absorber II (1-9), a stray light absorber III (1-10), a polarizer I (1-11), a polarizer II (1-12), a polarizer III (1-13), a beam splitter I (1-14), and a beam splitter II. (1-15), beam splitter III (1-16), fiber-to-waveguide coupler I (1-17), fiber-to-waveguide coupler II (1-18), fiber-to-waveguide coupler III (1-19), fiber-to-waveguide coupler IV (1-20), fiber-to-waveguide coupler V (1-21), fiber-to-waveguide coupler VI (1-22), end-face coupler I (1-23), end-face coupler II (1-24), end-face coupler III (1-25), detector I (1-26), detector II (1-27), detector III (1-28); The SLD chip (1-1) is connected to the input terminal of the 1-to-3 beam splitter (1-3) via the mode converter I (1-2); the three output terminals of the 1-to-3 beam splitter (1-3) are respectively connected to the first ports of the 2-to-2 beam splitter I (1-5), 2-to-2 beam splitter II (1-6), and 2-to-2 beam splitter III (1-7); the second ports of the 2-to-2 beam splitter I (1-5), 2-to-2 beam splitter II (1-6), and 2-to-2 beam splitter III (1-7) are respectively connected to the end-face coupler I (1-23) and end-face coupler II (1-24). The end-face coupler Ⅲ (1-25) is connected to detector Ⅰ (1-26), detector Ⅱ (1-27), and detector Ⅲ (1-28) respectively; the third ports of the two-to-two beam splitter Ⅰ (1-5), two-to-two beam splitter Ⅱ (1-6), and two-to-two beam splitter Ⅲ (1-7) are connected to stray light absorber Ⅰ (1-8), stray light absorber Ⅱ (1-9), and stray light absorber Ⅲ (1-10) respectively; the fourth ports of the two-to-two beam splitter Ⅰ (1-5), two-to-two beam splitter Ⅱ (1-6), and two-to-two beam splitter Ⅲ (1-7) The input terminals of polarizers I (1-11), II (1-12), and III (1-13) are connected to each other; the output terminals of polarizers I (1-11), II (1-12), and III (1-13) are connected to the input terminals of beam splitters I (1-14), II (1-15), and III (1-16), respectively; the output terminals of beam splitters I (1-14), II (1-15), and III (1-16) are connected to the input terminals of fiber-to-waveguide couplers I (1-17) and II (1-16), respectively. (1-18), fiber-to-waveguide coupler Ⅲ (1-19), fiber-to-waveguide coupler Ⅳ (1-20), fiber-to-waveguide coupler Ⅴ (1-21), and fiber-to-waveguide coupler Ⅵ (1-22) are respectively connected to the first channel (2-1), the second channel (2-2), the third channel (2-3), the fourth channel (2-4), the fifth channel (2-5), and the sixth channel (2-6) of the six-channel polarization-maintaining fiber array.

3. The lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 2, characterized in that, The passive components of the silicon-based hybrid integrated chip (1) include: a mode converter (1-2), a one-to-three beam splitter (1-3), a cross structure (1-4), a two-to-two beam splitter I (1-5), a two-to-two beam splitter II (1-6), a two-to-two beam splitter III (1-7), a stray light absorber I (1-8), a stray light absorber II (1-9), a stray light absorber III (1-10), a polarizer I (1-11), a polarizer II (1-12), a polarizer III (1-13), and a beam splitter. Beam splitter I (1-14), beam splitter II (1-15), beam splitter III (1-16), fiber-to-waveguide coupler I (1-17), fiber-to-waveguide coupler II (1-18), fiber-to-waveguide coupler III (1-19), fiber-to-waveguide coupler IV (1-20), fiber-to-waveguide coupler V (1-21), fiber-to-waveguide coupler VI (1-22), end-face coupler I (1-23), end-face coupler II (1-24), end-face coupler III (1-25); The passive device is integrated on a single silicon-based SiN chip; The SLD chip (1-1), detector I (1-26), detector II (1-27), and detector III (1-28) are integrated with a monolithic silicon-based SiN chip through end-face bonding to realize a silicon-based hybrid integrated chip (1).

4. A lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 1, characterized in that, The TEC temperature control chip in the control circuit (9) performs overall temperature control on the silicon-based hybrid integrated chip (1); The detector control module of the control circuit (9) receives the optical signal output from any detector output terminal and feeds it back to the SLD chip (1-1) for optical power regulation and compensation, so that the optical power of the detector remains constant during the rotation of the gyroscope.

5. A lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 1, characterized in that, The one-to-three beam splitter (1-3) adopts a 1×3 multimode interference (MMI) beam splitter structure; The two-to-two beam splitter I (1-5), two-to-two beam splitter II (1-6), and two-to-two beam splitter III (1-7) adopt the same 2×2 multimode interference (MMI) beam splitter structure to achieve a uniform beam splitting ratio, and are connected to a stray light absorber to absorb stray light with inherent loss.

6. A lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 1, characterized in that, The beam splitter I (1-14), beam splitter II (1-15), and beam splitter III (1-16) all adopt the same 1×2 Y-branch structure and have an operating wavelength range of 810nm~890nm. The cross structure (1-4) is formed by the perpendicular intersection of the waveguide of the first output port of the one-to-three beam splitter (1-3) and the waveguide of the second port of the two-to-two beam splitter II (1-6).

7. A lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 1, characterized in that, The polarizers I (1-11), II (1-12), and III (1-13) all adopt the same cascaded structure of curved waveguides with a large waveguide aspect ratio. The fiber-waveguide couplers I (1-17), II (1-18), III (1-19), IV (1-20), V (1-21), and VI (1-22) all adopt the same inverted conical structure to achieve mode field matching and are distributed in parallel at equal intervals on the same end face of the chip; and the spacing between two adjacent fiber-waveguide couplers is equal to the channel spacing of the six-channel polarization-maintaining fiber array (2), and the spacing between adjacent fiber-waveguide couplers is 250μm or 500μm.

8. A lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 1, characterized in that, The end-face couplers I (1-23), II (1-24), and III (1-25) all adopt the same linear tapered waveguide structure; The stray light absorbers I (1-8), II (1-9), and III (1-10) have identical structures. They are formed by deep etching and filled with light-absorbing material.

9. A lightweight, miniature three-axis multiplexed photonic chip gyroscope according to claim 1, characterized in that, The PZT modulator I (6), PZT modulator II (7), and PZT modulator III (8) are respectively placed at the center of fiber ring I (3), fiber ring II (4), and fiber ring III (5).

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