A thin-film lithium niobate heterogeneous integrated chip configuration for fiber optic gyroscopes

Abstract

This invention belongs to the fields of integrated optics and inertial sensing technology, specifically relating to a heterogeneous integrated chip configuration for fiber optic gyroscopes using thin-film lithium niobate. It achieves full-chip heterogeneous integration of fiber optic gyroscope functional devices using a thin-film lithium niobate hybrid photonic integrated chip. The discrete optical path components of the gyroscope are monolithically integrated and packaged, significantly reducing the size and cost of the optical path, minimizing fiber interconnections, and significantly reducing assembly process complexity, effectively improving the long-term reliability of the gyroscope performance. Leveraging mature silicon photonics CMOS technology, low-cost, large-scale mass production of miniature fiber optic gyroscopes can be achieved, meeting the miniaturization and lightweight requirements of future weapon systems.

Description

Technical Field

[0001] This invention belongs to the field of integrated optics and inertial sensing technology, and specifically relates to a heterogeneous integrated chip configuration of thin-film lithium niobate for fiber optic gyroscopes. Background Technology

[0002] Fiber optic gyroscopes, as core components of inertial navigation systems, are widely used in aviation navigation, munition guidance, and industrial automation. With modern warfare increasingly characterized by all-space and three-dimensional warfare, the demand for information-based, unmanned, and intelligent combat is rising. Unmanned aerial vehicle (UAV) swarms, tactical missiles, guided munitions, and unmanned vehicles are experiencing explosive growth, making small-size, low-cost, and scalable fiber optic gyroscopes, as a core technological support, an urgent need. However, traditional fiber optic gyroscopes use discrete fiber optic devices, resulting in large gyroscope sizes and requiring complex fiber coiling processes, leading to numerous and time-consuming manufacturing steps. Furthermore, the manufacturing process requires significant human intervention, making it difficult to guarantee process consistency, long-term reliability, and batch-to-batch stability. Simultaneously, small production scale and capacity result in high manufacturing costs. These shortcomings have become bottlenecks restricting the large-scale application of fiber optic gyroscopes. Summary of the Invention

[0003] The technical problem solved by this invention: In view of the current problems of large size, high power consumption and poor long-term consistency of fiber optic gyroscopes, this invention proposes a solution for implementing fiber optic gyroscopes using thin-film lithium niobate heterogeneous integrated chips.

[0004] The technical solution of the present invention:

[0005] A heterogeneous integrated chip configuration for fiber optic gyroscopes using thin-film lithium niobate is disclosed. The heterogeneous integrated chip is achieved by directly etching thin-film lithium niobate. The heterogeneous integrated chip configuration includes: SLD chip 1-1, isolator 1-2, light source-waveguide mode converter 1-3, coupler I1-5, polarizer 1-7, coupler II1-9, stray light absorption structure II1-10, electro-optic modulator 1-11, metal electrode 1-12, tilted output waveguide I1-13, fiber-optic-waveguide mode converter I1-14, tilted output waveguide II1-15, fiber-optic-waveguide mode converter II1-16, coupling grating 1-19, and detector chip 1-20.

[0006] The emitted light from SLD chip 1-1 is coupled into light source-waveguide mode converter 1-3 via isolator 1-2, and then connected to the first input terminal of coupler I1-5; the through terminal of coupler I1-5 is connected to the input terminal of polarizer 1-7; the output terminal of polarizer 1-7 is connected to one input terminal of coupler II1-9, the other input terminal of coupler II1-9 is connected to stray light absorption structure II1-10, and the two arms of the output terminal of coupler II1-9 are connected to the two arms of the input terminal of electro-optic modulator 1-11; after the light is modulated by an electric field applied by metal electrode 1-12, it is output from the two arms of the output terminal of electro-optic modulator 1-11 respectively; the two arms of the output terminal of electro-optic modulator 1-11 are connected to fiber-to-waveguide mode converter I1-14 and fiber-to-waveguide mode converter II1-16 via tilted output waveguide I1-13 and tilted output waveguide II1-15 respectively, and then connected to the polarization-maintaining fiber array of two channels. The second input terminal of coupler I1-5 is connected to detector chip 1-20 via coupling grating 1-19.

[0007] Furthermore, the heterogeneous integrated chip configuration also includes: stray light isolation structure I1-4, stray light absorption structure I1-6, stray light isolation structure II1-8, stray light isolation structure III1-17, and stray light isolation structure IV1-18.

[0008] Stray light isolation structure I1-4 is disposed on both sides of light source-waveguide mode converter 1-3;

[0009] Stray light absorption structure I1-6 is disposed on the surface of coupler I1-5;

[0010] Stray light isolation structure II1-8 is disposed around polarizer 1-7;

[0011] Stray light isolation structure III1-17 is disposed around the curved waveguide of electro-optic modulator 1-11;

[0012] Stray light isolation structure IV1-18 is disposed on both sides of coupling grating 1-19.

[0013] Furthermore, stray light isolation structures I1-4, II1-8, III1-17, and IV1-18, along with stray light absorption structures I1-6 and II1-10, are achieved by filling and covering the thin-film lithium niobate chip with photodamping material.

[0014] The SLD chip (1-1) and isolator (1-2) are aligned and surface-bonded with the light source-waveguide mode converter (1-3) by deeply etching trenches on the surface of thin-film lithium niobate and using flip-chip packaging; the detector chip (1-20) is coupled to the thin-film lithium niobate chip through a coupling grating (1-19).

[0015] The electro-optic modulator (1-11) achieves the electro-optic modulation effect by fabricating a patterned ridge waveguide and gold electrodes through shallow etching.

[0016] Furthermore, the coupler I1-5 is a 1×2 Y-branch structure, and the surface of the Y-branch is covered with a thin film of optical damping material; the coupler II1-9 is a 2×2 multimode interference coupling (MMI) structure, with one input end connected to the optical damping material, and the center working wavelengths of the two couplers are 850nm, 1310nm and 1550nm.

[0017] The polarizers 1-7 are cascaded curved waveguide polarizers, using flat waveguides with a large aspect ratio greater than 10, multiple curved cascades, and center operating wavelengths of 850nm, 1310nm and 1550nm.

[0018] Furthermore, the electro-optic modulator 1-11 is realized by directly etching a lithium niobate thin film, and the light is confined by the lithium niobate waveguide and mainly transmitted in the lithium niobate thin film;

[0019] The two arms of the electro-optic modulator 1-11 are confined in a lithium niobate film, and the light interacts with the electric field applied by the metal electrode 1-12. The modulation region of the electro-optic modulator 1-11 is bent twice, and the central working wavelengths are 850nm, 1310nm and 1550nm.

[0020] Furthermore, the light source-waveguide mode converter 1-3 adopts an inverted conical structure, with the end near the light source being narrower than the transmission waveguide, and the other end having the same width as the transmission waveguide;

[0021] The fiber-to-waveguide mode converters I1-14 and II1-16 adopt an inverted conical structure, with one end of the fiber narrower than the transmission waveguide and the other end having the same width as the transmission waveguide.

[0022] The coupling grating (1-19) has a duty cycle of 50% and a center working wavelength of 850nm, 1310nm and 1550nm.

[0023] Furthermore, the optical damping material is a metal, polymer, or ferromagnetic material.

[0024] Furthermore, the tilted output waveguide I1-13 and the tilted output waveguide II1-15 are double-layer inverted cone structures;

[0025] The tilted output waveguides I1-13 and II1-15 form an 82-degree angle with the end face of the heterogeneous integrated chip, with spacing of 250μm, 300μm, and 500μm, respectively.

[0026] Furthermore, an 8-degree inclined grinding process with a wider top and narrower bottom is performed on the end faces of the heterogeneous integrated chip near the fiber-to-waveguide mode converters I1-14 and II1-16.

[0027] To address the issues of large size, high power consumption, and poor long-term consistency in current fiber optic gyroscopes, this invention proposes a solution for implementing fiber optic gyroscopes using a thin-film lithium niobate heterogeneous integrated chip. This solution utilizes a thin-film lithium niobate hybrid photonic integrated chip to achieve full-chip heterogeneous integration of the fiber optic gyroscope's functional components. The discrete optical path components of the gyroscope are monolithically integrated and packaged, significantly reducing the size and cost of the optical path, minimizing fiber interconnections, and significantly reducing assembly process complexity, effectively improving the long-term reliability of the gyroscope's performance. Leveraging mature silicon photonics CMOS technology, low-cost, large-scale mass production of miniature fiber optic gyroscopes can be achieved, meeting the miniaturization and lightweight requirements of future weapon systems. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the thin-film lithium niobate heterogeneous integrated chip for fiber optic gyroscopes of the present invention;

[0029] Figure 2 (a) is a schematic diagram of a Y-branch coupler structure; (b) is a schematic diagram of a 2×2 MMI coupler structure.

[0030] Figure 3 Top view and cross-sectional view of the inverted conical mold conversion structure;

[0031] Figure 4 A schematic diagram of a stray light isolator for a light source and detector.

[0032] Figure 5 This is a schematic diagram of the cross-section of an electro-optic modulator;

[0033] Figure 6 This is a schematic diagram of an end-face inclined grinding structure. Detailed Implementation

[0034] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be described in detail and completely below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0035] The present invention will now be described in further detail with reference to the accompanying drawings:

[0036] To address the shortcomings of current fiber optic gyroscopes, such as large size, complex manufacturing process, and poor long-term consistency due to the use of discrete optical path devices, a heterogeneous integrated optical chip based on thin-film lithium niobate is provided.

[0037] The invention will be described in further detail with reference to the accompanying drawings.

[0038] See Figure 1 The fiber optic gyroscope heterogeneous integrated chip for thin-film lithium niobate as described in this invention includes: an SLD chip 1-1, an isolator 1-2, a light source-waveguide mode converter 1-3, a stray light isolation structure I1-4, a coupler I1-5, a stray light absorption structure I1-6, a polarizer 1-7, a stray light isolation structure II1-8, a coupler II1-9, a stray light absorption structure II1-10, an electro-optic modulator 1-11, a metal electrode 1-12, a tilted output waveguide I1-13, a fiber-optic-waveguide mode converter I1-14, a tilted output waveguide II1-15, a fiber-optic-waveguide mode converter II1-16, a stray light isolation structure III1-17, a stray light isolation structure IV1-18, a coupling grating 1-19, and a detector chip 1-20.

[0039] The emitted light from SLD chip 1-1 is coupled into light source-waveguide mode converter 1-3 via isolator 1-2, and then connected to the first input terminal of coupler I1-5; the through terminal of coupler I1-5 is connected to the input terminal of polarizer 1-7; the output terminal of polarizer 1-7 is connected to one input terminal of coupler II1-9, the other input terminal of coupler II1-9 is connected to stray light absorption structure II1-10, and the two arms of the output terminal of coupler II1-9 are connected to the two arms of the input terminal of electro-optic modulator 1-11; after the light is modulated by an electric field applied by metal electrode 1-12, it is output from the two arms of the output terminal of electro-optic modulator 1-11 respectively; the two arms of the output terminal of electro-optic modulator 1-11 are connected to fiber-to-waveguide mode converter I1-14 and fiber-to-waveguide mode converter II1-16 via tilted output waveguide I1-13 and tilted output waveguide II1-15 respectively, and then connected to the polarization-maintaining fiber array of two channels. The second input terminal of coupler I1-5 is connected to detector chip 1-20 via coupling grating 1-19.

[0040] The passive components in the optical path include: light source-waveguide mode converters 1-3, coupler I1-5, polarizer 1-7, coupler II1-9, tilted output waveguides I1-13 and II1-15, fiber-to-waveguide mode converters I1-14 and II1-16, and coupling grating 1-19, all monolithically integrated on a thin-film lithium niobate chip; stray light isolation structures I1-4, II1-8, and III1-17. The stray light isolation structure IV1-18, stray light absorption structure I1-6, and stray light absorption structure II1-10 are realized by filling and covering the thin-film lithium niobate chip with photodamping material; the SLD chip 1-1 and the isolator 1-2 are integrated with the thin-film lithium niobate chip by surface bonding in deep etched trenches; the detector chip 1-20 is integrated with the thin-film lithium niobate chip by vertical coupling with a grating; the electro-optic modulator 1-11 achieves electro-optic modulation effect by shallow etching to prepare a patterned ridge waveguide and gold electrode.

[0041] The SLD chip 1-1 and isolator 1-2 are assembled by deeply etching trenches on the surface of thin-film lithium niobate and using flip-chip bonding to align the mode spots of the SLD chip 1-1 with the light source-waveguide mode converter 1-3 and surface bond them. The emitted light from the SLD chip 1-1 enters the isolator 1-2 through spatial light. The detector chip 1-20 is vertically coupled to the thin-film lithium niobate chip through coupling grating 1-19 and surface mounted.

[0042] The coupler I1-5 is a 1×2 Y-branch structure, and the surface of the Y-branch is covered with a thin film of optical damping material; the coupler II1-9 is a 2×2 multimode interference coupling (MMI) structure, with one input end connected to the optical damping material, and the center working wavelengths of the two couplers are 850nm, 1310nm and 1550nm.

[0043] The polarizers 1-7 are cascaded curved waveguide polarizers, using flat waveguides with a large aspect ratio greater than 10, multiple curved cascades, and center operating wavelengths of 850nm, 1310nm and 1550nm.

[0044] The electro-optic modulator 1-11 is realized by directly etching a lithium niobate thin film. The light is confined by the lithium niobate waveguide and mainly transmitted in the lithium niobate thin film. The metal electrode 1-12 is made of gold and is in the form of a traveling wave electrode. The light confined in the lithium niobate thin film in both arms of the electro-optic modulator 1-11 interacts with the electric field applied by the metal electrode 1-12. The modulation region of the electro-optic modulator 1-11 is bent twice, and the central working wavelengths are 850nm, 1310nm and 1550nm.

[0045] The light source-waveguide mode converter 1-3 adopts an inverted conical structure, with the end near the light source narrower than the transmission waveguide and the other end having the same width as the transmission waveguide; the fiber-waveguide mode converters I1-14 and II1-16 adopt an inverted conical structure, with the end near the fiber narrower than the transmission waveguide and the other end having the same width as the transmission waveguide; the center operating wavelengths of the coupling grating 1-19 are 850nm, 1310nm, and 1550nm.

[0046] The stray light isolation structures I1-4, II1-8, III1-17, and IV1-18 are achieved by deeply etching and filling the surface of a thin-film lithium niobate chip with a light damping material.

[0047] The stray light absorption structure I1-6 is realized by covering the surface of coupler I1-5 with a thin film of optical damping material and patterning it; the stray light absorption structure II1-10 is realized by deeply etching and filling the surface of a thin film lithium niobate chip with optical damping material, and is connected to one input end of coupler II1-9 through a waveguide.

[0048] The materials used in the stray light isolation structure and absorption structure are metals, polymers, ferromagnetic materials, etc.

[0049] The tilted output waveguides I1-13 and II1-15 are at an angle of 82 degrees to the end face of the heterogeneous integrated chip, with spacing of 250μm, 300μm, and 500μm, respectively.

[0050] An 8-degree inclined grinding process with a wider top and narrower bottom is performed on the end faces of the heterogeneous integrated chip near the fiber-to-waveguide mode converters I1-14 and II1-16.

[0051] See Figure 1 The heterogeneous integrated chip for fiber optic gyroscopes of the present invention mainly includes: an SLD chip 1-1, an isolator 1-2, a light source-waveguide mode converter 1-3, a stray light isolation structure I1-4, a coupler I1-5, a stray light absorption structure I1-6, a polarizer 1-7, a stray light isolation structure II1-8, a coupler II1-9, a stray light absorption structure II1-10, an electro-optic modulator 1-11, a metal electrode 1-12, a tilted output waveguide I1-13, a fiber-optic-waveguide mode converter I1-14, a tilted output waveguide II1-15, a fiber-optic-waveguide mode converter II1-16, a stray light isolation structure III1-17, a stray light isolation structure IV1-18, a coupling grating 1-19, and a detector chip 1-20.

[0052] The broadband light emitted by SLD chip 1-1 contains two different polarization modes, TE and TM. It is efficiently coupled into coupler I1-5 via isolator 1-2 and light source-waveguide mode converter 1-3. The mode size of the light spot is effectively enlarged by light source-waveguide mode converter 1-3. Light not coupled into coupler I1-5 is absorbed and suppressed by stray light isolation structure I1-4 after being amplified in mode size. The 3dB stray light generated during light transmission in coupler I1-5 is fully absorbed by the surface-covered optical damping thin film stray light absorption structure I1-6. The transmitted light enters polarizer 1-7. Due to the different effective refractive indices and mode sizes of the TE and TM polarization modes during transmission, the TM mode light is gradually absorbed and attenuated during transmission, ultimately leaving mainly the TE mode light for transmission in the waveguide. The dissipated light is isolated by the curved stray light isolation structure II1-8. Subsequently, the light enters coupler II1-9. The 3dB stray light generated during light transmission is absorbed by the stray light absorption structure II1-10 after transmission through the waveguide. The light at the output of coupler II1-9 is split into two beams and enters... The two arms of the electro-optic modulator 1-11 have their transmitted light confined by SiN waveguides. Light concentrated in the lithium niobate film passes through the metal electrodes 1-12, where an external electric field adds a phase difference. From the output of the electro-optic modulator 1-11, the two arms connect to the tilted output waveguides I1-13 and II1-15, respectively. Stray light generated at the bends inside the modulator is absorbed, attenuated, and effectively isolated by the bent stray light isolation structure III1-17. The transmitted light then passes through fiber-to-waveguide mode converters I1-14 and II1-16, respectively, and is connected to two channels. The polarization-maintaining fiber array achieves efficient end-face coupling with low backscatter and low back reflection. After two beams of light propagate in the fiber ring in clockwise and counterclockwise directions respectively and meet the coherence condition, the Sagnac effect is generated when the fiber rotates around its central axis, causing the intensity of the interference light to change after the two beams are coupled. When the interference light returns to the coupler I1-5 along the optical path, it is output from the other input end and vertically coupled into the detector chip 1-20 through the coupling grating 1-19. The light that is not coupled in is absorbed and effectively isolated by the stray light isolation structure IV1-18 after being amplified by the mode field.

[0053] In one implementation, coupler I1-5 adopts a 1×2 Y-branch structure, and coupler II1-9 adopts a 2×2 MMI structure, with center operating wavelengths of 850nm, 1310nm, and 1550nm respectively. The Y-branch structure achieves a 1:1 splitting ratio. 3dB stray light generated during transmission is absorbed by a thin film of photodamping material covering the surface and converted into heat energy to prevent stray light crosstalk on the chip and interference with normal gyroscope signal detection. The 2×2 MMI structure also achieves a 1:1 splitting ratio, and 3dB stray light can be transmitted through a waveguide to a stray light absorption structure for absorption. To reduce device losses and improve the splitting ratio, this embodiment of the invention optimizes the design of the Y-branch structure and the MMI coupler, see [link to relevant documentation]. Figure 2 In this invention, the thin-film lithium niobate waveguide has a width of 1 μm and a height of 300 nm, with a device center wavelength of 1310 nm; the designed MMI coupler has an interference region width of 12 μm and a length of 68 μm, an input-output conical structure width of 3 μm and a length of 300 μm, and a beam splitting ratio of 1:1; the designed Y-branch structure has a branch spacing of 300 nm, an input conical structure length of 300 μm, an output two-arm spacing of 300 μm, a bent waveguide length of 800 μm, a bending radius of approximately 1000 μm, and a beam splitting ratio of 1:1.

[0054] In one implementation, the light source-waveguide mode converters 1-3, I1-14, and II1-16 all adopt an inverted conical structure, with a 50% duty cycle for the coupling grating 1-19, and center operating wavelengths of 850nm, 1310nm, and 1550nm, respectively. (See [reference to inverted conical structure]). Figure 3 In a 300nm thick SiN waveguide, the mode spot diameter is approximately 6.5μm. By designing a tapered coupling structure, the end-face coupling efficiency can be effectively improved. Specifically, the inverted tapered region is 400μm long and 300nm wide; the regular tapered region is 500μm long and 2.5μm wide. Both achieve coupling efficiencies exceeding 90%.

[0055] As one implementation, the polarizers 1-7 employ cascaded bent waveguides. The polarization principle is as follows: Different polarization states (TE and TM modes) in the waveguide have different mode field distributions and effective refractive indices. Differences between modes lead to varying polarization-dependent losses and mode dispersion. By designing a specific bending radius for the waveguide, the effective refractive index of the TM mode is lowered, increasing its transmission loss, while the TE mode transmits with extremely low loss. Through polarizers 1-7, a high polarization extinction ratio can be achieved. The cascaded bent waveguides have a bending radius of 100 μm, and multiple cascaded stages can achieve an extinction ratio >80 dB. Simultaneously, the input and output ports can be misaligned, reducing optical signal crosstalk.

[0056] As one implementation method, such as Figure 4As shown, the stray light isolation structures I1-4, II1-8, III1-17, and IV1-18 are implemented by deeply etching and filling the surface of a thin-film lithium niobate chip with photodamping material. The stray light absorption structure I1-6 is implemented by covering the surface of coupler I1-5 with a thin film of photodamping material and patterning it; the stray light absorption structure II1-10 is implemented by deeply etching and filling the surface of a thin-film lithium niobate chip with photodamping material, and is connected to one input terminal of coupler II1-9 via a waveguide. The stray light isolation and absorption structures can effectively suppress stray light crosstalk on the chip surface, effectively improving the gyroscope's signal-to-noise ratio and detection accuracy.

[0057] In one implementation, the electro-optic modulator 1-11 is achieved by directly etching a lithium niobate thin film. Light is confined by the lithium niobate waveguide and primarily transmitted within the lithium niobate thin film. Metal electrodes 1-12 are deposited on the lithium niobate thin film, and finally, a layer of SiO2 is applied. (See [link to previous document]). Figure 5 This method achieves modulation by applying an electric field to the electrodes and allowing the light in the lithium niobate film to interact, thus enabling on-chip modulation. Covering the film with SiO2, which has a higher relative permittivity than exposed air, enhances the interaction of the electric field with the light in the lithium niobate film, thereby improving the modulation effect. The SiO2 thickness is 800 nm. Furthermore, the gold electrode is selected with a width of 80 μm and a thickness of 1 μm. This dimensional optimization effectively reduces traveling wave loss in the metal and allows for better impedance and refractive index matching.

[0058] As one implementation, the tilted output waveguides I1-13 and II1-15 form an 82-degree angle with the right-side end face of the chip, with spacing of 250μm, 300μm, and 500μm, respectively; furthermore, the chip grinding end faces 1-21 are ground at an 8-degree angle, wider at the top and narrower at the bottom, see [reference needed]. Figure 6 By employing both waveguide tilting output and end-face tilting grinding, back reflection and backscattering between the chip and the fiber array can be effectively reduced, effectively suppressing stray light from entering the chip surface and causing crosstalk.

Claims

1. A heterogeneous integrated chip configuration for a thin-film lithium niobate fiber optic gyroscope, characterized in that, The heterogeneous integrated chip is realized by direct etching of thin-film lithium niobate. The heterogeneous integrated chip configuration includes: SLD chip (1-1), isolator (1-2), light source-waveguide mode converter (1-3), coupler I (1-5), polarizer (1-7), coupler II (1-9), stray light absorption structure II (1-10), electro-optic modulator (1-11), metal electrode (1-12), tilted output waveguide I (1-13), fiber-to-waveguide mode converter I (1-14), tilted output waveguide II (1-15), fiber-to-waveguide mode converter II (1-16), coupling grating (1-19), and detector chip (1-20). The emitted light from the SLD chip (1-1) is coupled into the light source-waveguide mode converter (1-3) through the isolator (1-2), and then connected to the first input terminal of coupler I (1-5); the through terminal of coupler I (1-5) is connected to the input terminal of polarizer (1-7); the output terminal of polarizer (1-7) is connected to one input terminal of coupler II (1-9), the other input terminal of coupler II (1-9) is connected to stray light absorption structure II (1-10), and the two arms of the output terminal of coupler II (1-9) are connected to the two arms of the input terminal of electro-optic modulator (1-11). The light passes through the metal electrode (1-12) and is modulated by an electric field. It is then output from the two arms of the output end of the electro-optic modulator (1-11). The two arms of the output end of the electro-optic modulator (1-11) are connected to the fiber-to-waveguide mode converter I (1-14) and the fiber-to-waveguide mode converter II (1-16) via the tilted output waveguide I (1-13) and the tilted output waveguide II (1-15), respectively, and then connected to the polarization-maintaining fiber array of the two channels. The second input end of the coupler I (1-5) is connected to the detector chip (1-20) via the coupling grating (1-19). The heterogeneous integrated chip configuration further includes: stray light isolation structure I (1-4), stray light absorption structure I (1-6), stray light isolation structure II (1-8), stray light isolation structure III (1-17), and stray light isolation structure IV (1-18). Stray light isolation structure I (1-4) is set on both sides of the light source-waveguide mode converter (1-3); Stray light absorption structure I (1-6) is disposed on the surface of coupler I (1-5); Stray light isolation structure II (1-8) is located around the polarizer (1-7); Stray light isolation structure III (1-17) is disposed around the curved waveguide of electro-optic modulator (1-11); Stray light isolation structure IV (1-18) is disposed on both sides of coupling grating (1-19); Stray light isolation structures I (1-4), II (1-8), III (1-17), and IV (1-18), along with stray light absorption structures I (1-6) and II (1-10), are achieved by filling and covering the thin-film lithium niobate chip with photodamping material. The SLD chip (1-1) and isolator (1-2) are connected by deep etching trenches on the surface of thin-film lithium niobate and by flip-chip bonding to align the mode spots of the SLD chip (1-1) with the light source-waveguide mode converter (1-3) and surface bond them; the detector chip (1-20) is coupled to the thin-film lithium niobate chip through a coupling grating (1-19). The electro-optic modulator (1-11) achieves the electro-optic modulation effect by fabricating a patterned ridge waveguide and gold electrodes through shallow etching; The coupler I (1-5) is a 1×2 Y-branch structure, and the surface of the Y-branch is covered with a thin film of optical damping material; the coupler II (1-9) is a 2×2 multimode interference coupling (MMI) structure, one of which is connected to the optical damping material, and the center working wavelengths of the two couplers are 850nm, 1310nm and 1550nm respectively. The polarizers (1-7) mentioned above are cascaded curved waveguide polarizers, using flat waveguides with an aspect ratio greater than 10, multiple stages of curved cascade, and center operating wavelengths of 850nm, 1310nm and 1550nm; The light source-waveguide mode converter (1-3) adopts an inverted cone structure, with the end near the light source narrower than the transmission waveguide, and the other end having the same width as the transmission waveguide.

2. The heterogeneous integrated chip configuration for a fiber optic gyroscope using thin-film lithium niobate according to claim 1, characterized in that, The electro-optic modulator (1-11) is realized by directly etching a lithium niobate thin film, and the light is confined by the lithium niobate waveguide and mainly transmitted in the lithium niobate thin film; The two arms of the electro-optic modulator (1-11) are confined in a lithium niobate film and interact with the electric field applied by the metal electrode (1-12). The modulation region of the electro-optic modulator (1-11) is bent twice, and the central working wavelengths are 850nm, 1310nm and 1550nm.

3. The heterogeneous integrated chip configuration for a fiber optic gyroscope using thin-film lithium niobate according to claim 1, characterized in that, Fiber-to-waveguide mode converter I (1-14) and fiber-to-waveguide mode converter II (1-16) adopt an inverted conical structure, with one end of the fiber narrower than the transmission waveguide and the other end having the same width as the transmission waveguide. The coupling grating (1-19) has a duty cycle of 50% and a center working wavelength of 850nm, 1310nm and 1550nm.

4. The heterogeneous integrated chip configuration for a fiber optic gyroscope using thin-film lithium niobate according to claim 1, characterized in that, The light damping material is a metal or a polymer.

5. The heterogeneous integrated chip configuration for a fiber optic gyroscope using thin-film lithium niobate according to claim 1, characterized in that, The tilted output waveguide I (1-13) and tilted output waveguide II (1-15) are double-layer inverted cone structures; The tilted output waveguide I (1-13) and tilted output waveguide II (1-15) form an 82-degree angle with the end face of the heterogeneous integrated chip, and the spacing between the tilted output waveguide I (1-13) and tilted output waveguide II (1-15) is 250µm, 300µm or 500µm.

6. The heterogeneous integrated chip configuration for a fiber optic gyroscope using thin-film lithium niobate according to claim 1, characterized in that, An 8-degree inclined grinding process with a wider top and narrower bottom is performed on the end face of the heterogeneous integrated chip near the fiber-to-waveguide mode converter I (1-14) and the fiber-to-waveguide mode converter II (1-16).

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