Three-axis modulator chip structure and three-axis fiber-optic gyroscope

Abstract

The invention provides a three-axis modulator chip structure and a three-axis fiber-optic gyroscope. The three-axis modulator chip structure comprises an electro-optical modulation chip, a first optical fiber and a second optical fiber, the input fiber is connected with the side of the chip. The input waveguide is embedded in the top surface of the chip, and the first end is coupled with the input fiber; a main port of the one-to-three coupler is coupled with the second end of the input waveguide; first branch ports of the three first one-to-two couplers are respectively coupled with three branch ports of the one-to-three coupler, second branch ports of the three first one-to-two couplers are respectively coupled with the three photoelectric detectors, and total ports of the three first one-to-two couplers are respectively coupled with total ports of the three second one-to-two couplers; each group of Y waveguide modulators comprises a Y waveguide and a modulation electrode, and first ends of two branch arms of the Y waveguide are coupled with two branch ports of the second one-to-two coupler; each output optical fiber group comprises two output optical fibers which are respectively coupled with the second ends of the two branch arms of the Y waveguide; the sealing cover covers the top surface of the chip. Welding is not needed, the assembling difficulty is reduced, and the overall size is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber optic gyroscopes, and in particular to a three-axis modulator chip structure and a three-axis fiber optic gyroscope. Background Art

[0002] Fiber optic gyroscope is a high-performance inertial sensing device based on the Sagnec effect, which has the characteristics of full solid-state, low noise, strong resistance to environmental interference, and full precision coverage. With the development of inertial guided missiles, drones, the Internet of Things, and autonomous driving technology, higher requirements are placed on the SWaP (size, weight, power consumption, and cost) comprehensive performance indicators of medium and low precision fiber optic gyroscopes. In order to expand the application field and form a competitive advantage with MEMS gyroscopes (micromechanical gyroscopes), traditional fiber optic gyroscopes must also be transformed in the direction of miniaturization, low cost, and high reliability.

[0003] In a traditional three-axis fiber optic gyroscope, the coupler, detector, and modulator are all independent components. Optical fibers are used to connect the coupler and detector, the couplers and the couplers, and the couplers and modulators. In addition, each independent component needs to be fused with the optical fiber to connect the optical path. Therefore, it has problems such as large size, complex assembly, and high cost, which is not conducive to engineering production. Summary of the invention

[0004] In view of this, the present invention provides a three-axis modulator chip structure and a three-axis fiber optic gyroscope to solve the above technical problems.

[0005] The three-axis modulator chip structure provided by the present invention includes: Electro-optical modulation chip; An input optical fiber, the input optical fiber being fixedly connected to a side surface of the electro-optic modulation chip; An input waveguide, wherein the input waveguide is embedded in the top surface of the electro-optic modulation chip and a first end of the input waveguide is coupled to the input optical fiber; A one-to-three coupler, wherein a total port of the one-to-three coupler is coupled to the second end of the input waveguide; three first one-to-two couplers, wherein the first branch ports of the three first one-to-two couplers are respectively coupled with the three branch ports of the one-to-three coupler through transmission waveguides; Three photodetectors, the three photodetectors are respectively fixedly connected to the side surfaces of the electro-optic modulation chip, and are respectively coupled to the second branch ports of the three first one-to-two couplers through transmission waveguides; three second one-to-two couplers, wherein the total ports of the three second one-to-two couplers are respectively coupled with the total ports of the three first one-to-two couplers through transmission waveguides; Three groups of Y-waveguide modulators, each group of the Y-waveguide modulators includes a Y-waveguide and a modulation electrode, the Y-waveguide includes a first branch arm and a second branch arm, the modulation electrodes are arranged on both sides of the extension direction of the first branch arm and the second branch arm, the first ends of the first branch arm and the second branch arm of each group of the Y-waveguide modulator are respectively coupled to two branch ports of one of the second one-to-two couplers, and the Y-waveguide modulator, the one-to-three coupler, the first one-to-two coupler and the second one-to-two coupler are respectively fixedly connected to the top surface of the electro-optical modulation chip; Three output fiber groups, the three output fiber groups are respectively fixedly connected to the side of the electro-optic modulation chip and are arranged one-to-one with the three groups of Y-waveguide modulators, each of the output fiber groups includes two output fibers, and the two output fibers are respectively coupled to the second ends of the first branch arm and the second branch arm of the corresponding Y-waveguide; A cover is provided to cover the top surface of the electro-optic modulation chip and is fixedly connected to the electro-optic modulation chip.

[0006] Optionally, the three-axis modulator chip structure further includes: a pad, which is fixedly connected to the top surface of the electro-optical modulation chip and electrically connected to the modulation electrode for connecting to an external power supply.

[0007] Optionally, at least a portion of the transmission waveguide is configured to be arc-shaped.

[0008] Optionally, the three photodetectors are arranged on different sides of the electro-optic modulation chip.

[0009] Optionally, absorption electrodes are provided on both sides of the extension direction of the transmission waveguide.

[0010] Optionally, the absorption electrode is made of gold.

[0011] Optionally, the electro-optic modulation chip is a lithium niobate thin film chip.

[0012] Optionally, the lithium niobate thin film chip includes a silicon substrate layer, a silicon dioxide layer, a lithium niobate thin film layer and a silicon dioxide buffer layer stacked in sequence, and the input waveguide is embedded in the silicon dioxide buffer layer.

[0013] Optionally, the input waveguide is etched on the lithium niobate thin film layer, and the silicon dioxide buffer layer covers the input waveguide.

[0014] The present invention also provides a three-axis fiber optic gyroscope, comprising a light source and three fiber rings, and also comprising the three-axis modulator chip structure described in any of the above items, wherein the light source is coupled to the input fiber of the three-axis modulator chip structure, and the three fiber rings are respectively coupled to three output fiber groups.

[0015] Compared with the prior art, the above technical solution provided by the present invention has at least the following beneficial effects: The three-axis modulator chip structure and the three-axis fiber optic gyroscope of the present invention are adopted, and waveguides are used to realize coupling between the coupler and the input optical fiber, between the couplers, and between the coupler and the photodetector, thereby abandoning the optical fiber connection and eliminating the need for a fusion process, thereby reducing the cost and assembly difficulty and improving the reliability level. In addition, the coupler, Y-waveguide modulator and photodetector are all integrated into the electro-optic modulation chip, reducing the overall volume and meeting the application requirements of miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A three-dimensional schematic diagram of a three-axis modulator chip structure according to an embodiment of the present invention; Figure 2 for Figure 1 A top view of the three-axis modulator chip structure shown; Figure 3 for Figure 1 Schematic diagram of a photodetector with a three-axis modulator chip structure shown; Figure 4 for Figure 1 Schematic diagram of the electro-optic modulation chip with a three-axis modulator chip structure shown.

[0017] Reference numerals: 1: electro-optic modulation chip; 101: silicon substrate layer; 102: silicon dioxide layer; 103: lithium niobate thin film layer; 104: silicon dioxide buffer layer; 2: input optical fiber; 3: input waveguide; 4: one-to-three coupler; 5: first one-to-two coupler; 6: photodetector; 7: second one-to-two coupler; 8: Y-waveguide modulator; 81: Y-waveguide; 82: modulation electrode; 9: output optical fiber group; 91: output optical fiber; 10: solder pad; 11: absorption electrode; 12: transmission waveguide. DETAILED DESCRIPTION

[0018] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only simplified descriptions for the convenience of describing the present invention, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0019] Figure 1 A three-dimensional schematic diagram of a three-axis modulator chip structure according to an embodiment of the present invention; Figure 2 for Figure 1 A top view of the three-axis modulator chip structure shown; Figure 3 for Figure 1 Schematic diagram of a photodetector with a three-axis modulator chip structure. Figure 1-Figure 3 As shown, the three-axis modulator chip structure includes an electro-optical modulation chip 1, an input optical fiber 2, an input waveguide 3, a one-to-three coupler 4, three first one-to-two couplers 5, three photodetectors 6, three second one-to-two couplers 7, three groups of Y-waveguide modulators 8, three output optical fiber groups 9 and a cover (not shown).

[0020] The input optical fiber 2 is fixedly connected to the side of the electro-optic modulation chip 1; the input waveguide 3 is embedded in the top surface of the electro-optic modulation chip 1, and its first end is coupled to the input optical fiber 2; the total port of the one-to-three coupler 4 is coupled to the second end of the input waveguide 3; the first branch ports of the three first one-to-two couplers 5 are respectively coupled to the three branch ports of the one-to-three coupler 4 through the transmission waveguide 12; the three photodetectors 6 are respectively fixedly connected to the side of the electro-optic modulation chip 1, and are respectively coupled to the second branch ports of the three first one-to-two couplers 5 through the transmission waveguide 12; the total ports of the three second one-to-two couplers 7 are respectively coupled to the total ports of the three first one-to-two couplers 5 through the transmission waveguide 12; each group of Y-waveguide modulators 8 includes a Y-waveguide 81 and a modulation electrode 82, and the Y-waveguide 81 includes a first branch arm and a second Modulation electrodes 82 are arranged on both sides of the extension direction of the branch arm, the first branch arm and the second branch arm. The first ends of the first branch arm and the second branch arm of each group of Y-waveguide modulators 8 are respectively coupled with the two branch ports of a second one-to-two coupler 7. The Y-waveguide modulator 8, the one-to-three coupler 4, the first one-to-two coupler 5 and the second one-to-two coupler 7 are respectively fixedly connected to the top surface of the electro-optical modulation chip 1; three output optical fiber groups 9 are respectively fixedly connected to the side surfaces of the electro-optical modulation chip 1 and are arranged one-to-one with the three groups of Y-waveguide modulators 8. Each output optical fiber group 9 includes two output optical fibers 91, and the two output optical fibers 91 are respectively coupled with the second ends of the first branch arm and the second branch arm of the corresponding Y-waveguide 81; a cover is provided on the top surface of the electro-optical modulation chip 1 and is fixedly connected to the electro-optical modulation chip 1.

[0021] When in use, the input optical fiber 2 is coupled to an external light source, the output ends of the three photodetectors 6 are respectively connected to the external signal processing unit for communication, the modulation electrode 82 is electrically connected to the external power supply, the external signal processing unit is connected to the control end of the external power supply for communication, and the two output optical fibers 91 of each output optical fiber group 9 are respectively coupled to the connecting optical fibers at the head and tail ends of a fiber ring. The light emitted by the external light source is transmitted to the input optical fiber 2, and further transmitted to the input waveguide 3 coupled with the input optical fiber 2. When the light is transmitted to the one-to-three coupler 4 through the input waveguide 3, it is equally divided into three paths, and is respectively transmitted to the three first one-to-two couplers 5 through the three branch ports and the coupled transmission waveguide 12, and is respectively transmitted to the total ports of the three second one-to-two couplers 7 through the total ports of the three first one-to-two couplers 5, and then is transmitted to the first branch arm and the second branch arm of the Y waveguide 81 through the two branch ports of the three second one-to-two couplers 7. When transmitting in the first branch arm and the second branch arm, the modulation electrodes 82 on both sides are applied with voltage under the action of the external power supply, and the optical signals in the two branch arms will be electro-optically modulated, and the light carrying the modulated signal continues to be transmitted to the two output optical fibers 91 coupled with the two branch arms of the Y waveguide 81, and is further transmitted to the optical fiber ring coupled thereto through the two output optical fibers 91. After the optical signal passes through the optical fiber ring, the optical signal carrying the Sacknak ​​phase difference will pass through the output optical fiber 91 again, and be transmitted to the first branch arm and the second branch arm of the Y waveguide 81, and after being modulated by the modulation electrode 82 again, it will be transmitted to each second one-to-two coupler 7, and transmitted to the total port of the first one-to-two coupler 5 through the total port of the second one-to-two coupler 7, wherein part of the optical signal is transmitted to the coupled photodetector 6 through the second branch port of the first one-to-two coupler 5 to receive the optical signal, and the optical signal is converted into a current signal in the photodetector 6, and the current signal is further output to the signal processing unit, and useful phase information is extracted after calculation. At the same time, the control end of the external power supply can be further adjusted according to the converted current signal to adjust the modulation voltage applied to the modulation electrode 82.

[0022] The three-axis modulator chip structure of the present invention is adopted, and waveguides are used to realize coupling between the coupler and the input optical fiber 2, between the couplers, and between the coupler and the photodetector 6, thereby abandoning the optical fiber connection and eliminating the need for a fusion process, thereby reducing the cost and assembly difficulty and improving the reliability level. In addition, the coupler, Y-waveguide modulator 8 and photodetector 6 are all integrated into the electro-optic modulation chip 1, reducing the overall volume and meeting the application requirements of miniaturization.

[0023] like Figure 1 and Figure 2As shown, in this embodiment, the electro-optical modulation chip 1 is in the shape of a rectangular parallelepiped as a whole, and the input optical fiber 2 is fixed to the middle position of the right side of the electro-optical modulation chip 1 by means of a FA optical fiber array head. The input waveguide 3 is parallel to the front and rear sides of the electro-optical modulation chip 1, and the right end is coupled to the input optical fiber 2, and the left end is coupled to the total port of the one-to-three coupler 4. The right end of the one-to-three coupler 4 in the figure is the total port, and the left end is three branch ports, which are respectively coupled to the first branch ports of the three first one-to-two couplers 5 by means of a transmission waveguide 12. The three photodetectors 6 are respectively fixed to the side of the electro-optical modulation chip 1, and the second branch ports of the three first one-to-two couplers 5 are respectively coupled to the three photodetectors 6 by means of the transmission waveguide 12 extending to the side of the electro-optical modulation chip 1. Three groups of Y waveguide modulators 8 are arranged in parallel, as shown in FIG. Figure 1 and Figure 2 As shown, two groups of Y waveguide modulators 8 are distributed on the upper side of the input waveguide 3, and one group of Y waveguide modulators 8 is distributed on the lower side. The three second one-to-two couplers 7 are arranged in one-to-one correspondence with the three groups of Y waveguide modulators 8. The total ports of the three second one-to-two couplers 7 are respectively coupled with the total ports of the three first one-to-two couplers 5 by means of the transmission waveguide 12, and the two branch ports of a second one-to-two coupler 7 are respectively coupled with the left ends of the first branch arm and the second branch arm of a Y waveguide modulator 8. The right ends of the first branch arm and the second branch arm of each group of Y waveguide modulators 8 are respectively coupled with two output optical fibers 91 in the same output optical fiber group 9, and the two output optical fibers 91 in the same output optical fiber group 9 are used to couple with the external optical fiber ring. Figure 3 for Figure 1 Schematic diagram of a photodetector with a three-axis modulator chip structure, as shown in Figure 1-Figure 3 As shown, the photodetector 6 adopts a vertical structure, and the photosensitive surface is mounted on a ceramic substrate with an electrode pattern. The maximum optical signal reception is achieved through the coupling alignment of the transmission waveguide 12, and then converted into an electrical signal output. Compared with the optical fiber fusion, the coupling design of the photodetector 6 and the transmission waveguide 12 saves the fusion process, and the fixing to the electro-optical modulation chip 1 improves the integration of the overall structure. The Y-waveguide modulator 8 and the optical fiber ring are both mature existing technologies, and their specific structures and working principles are not repeated here. The cover can be detachably connected to the electro-optical modulation chip 1 and is made of transparent material to facilitate the observation of the internal independent components. According to the actual application, the specific specifications and models of the electro-optical modulation chip 1, the specific layout position of the Y-waveguide modulator 8 on the electro-optical modulation chip 1, the specific fixed position of the photodetector 6 on the electro-optical modulation chip 1, the specifications and extension length of the input waveguide 3 and the transmission waveguide 12 can all be adjusted.

[0024] Optionally, the three-axis modulator chip structure further includes a pad 10, which is fixedly connected to the top surface of the electro-optical modulation chip 1 and electrically connected to the modulation electrode 82 for connection to an external power source. The pad 10 has a large area, and the modulation electrode 82 is pre-connected to the pad 10. When a modulation voltage needs to be applied to the modulation electrode 82, the external power source is directly electrically connected to the pad 10 to achieve electrical connection with the modulation electrode 82, that is, the connection area between the modulation electrode 82 and the external power source is increased, thereby reducing the difficulty of connecting to the external power source.

[0025] like Figure 1 and Figure 2 As shown, in this embodiment, two pads 10 are fixed on the upper surface of the electro-optical modulation chip 1, and are close to the front end side of the electro-optical modulation chip 1, which are used to connect the positive and negative poles of the external power supply respectively, and are electrically connected to the modulation electrode 82 of the Y-waveguide modulator 8. In this embodiment, the modulation electrode 82 adopts a push-pull modulation electrode, and is made of gold. The two modulation electrodes 82 between the first branch arm and the second branch arm arranged above and below the Y-waveguide 81 are connected at one end, and then electrically connected to the pad 10 together, which can achieve low energy consumption. The push-pull modulation electrode 82 is a mature prior art, and its specific arrangement and working principle are not repeated here. According to the actual application situation, the specifications and dimensions of the pad 10 and the specific fixed position on the top surface of the electro-optical modulation chip 1 can be adjusted.

[0026] Optionally, at least part of the transmission waveguide 12 is configured to be arc-shaped. The transmission waveguide 12 is configured to be arc-shaped, which can not only meet the length requirement of the waveguide for light transmission, but also reduce the straight extension length of the transmission waveguide 12 on the surface of the electro-optic modulation chip 1 by bending into an arc, which is conducive to further miniaturization of the overall structure.

[0027] like Figure 1 and Figure 2 As shown, in this embodiment, the transmission waveguide 12 between the photodetector 6 and the first one-to-two coupler 5, the transmission waveguide 12 between the first one-to-two coupler 5 and the second one-to-two coupler 7, and the transmission waveguide 12 between the one-to-three coupler 4 and the first one-to-two coupler 5 are at least partially configured as curved arcs, and the extension direction of the transmission waveguide 12 is changed by bending to avoid the transmission waveguide 12 extending too long in a certain direction, thereby realizing the miniaturization design of the overall structure. According to the actual application, the bending direction and specific bending arc of the transmission waveguide 12 can be adjusted.

[0028] Optionally, three photodetectors 6 are arranged on different sides of the electro-optic modulation chip 1. This arrangement reduces the crosstalk of signals between different channels by spatially isolating the photodetectors 6.

[0029] like Figure 1 and Figure 2As shown, in this embodiment, three photodetectors 6 are respectively fixed on the front side, the rear side and the right side surface of the electro-optic modulation chip 1, and the distance between the three is relatively large, which minimizes signal crosstalk. According to the actual application, the specific arrangement position of the photodetector 6 on the electro-optic modulation chip 1 can be adjusted.

[0030] Optionally, absorption electrodes 11 are provided on both sides of the extension direction of the transmission waveguide 12. Since there will be leakage of optical signals on both sides of the curved waveguide, and the leakage light will produce coupling crosstalk with the signal light of different channels to affect the accuracy of the gyro system, in order to reduce the crosstalk, the absorption electrodes 11 are arranged on both sides of the curved transmission waveguide 12 to absorb the leakage light by utilizing the property that metal has a large absorption of optical signals.

[0031] In this embodiment, the width of the absorption electrode 11 is about 200-300 μm, and the absorption electrode 11 can be manufactured simultaneously with the modulation electrode 82 without adding any process steps.

[0032] Optionally, the absorption electrode 11 is made of gold. The design of the absorption electrode 11 made of gold can greatly absorb the leaked light, further reduce the crosstalk between channels, and improve the accuracy of the fiber optic gyroscope.

[0033] Optionally, the electro-optic modulation chip 1 uses a lithium niobate thin film chip. Lithium niobate is an excellent electro-optic modulation material. By using the lithium niobate thin film chip as a material platform for design and manufacture, high-efficiency electro-optic modulation can be achieved through the modulation electrode 82, which has the advantages of small half-wave voltage, good linearity, large bandwidth, high polarization extinction ratio, small size and easy integration.

[0034] Optionally, the lithium niobate thin film chip includes a silicon substrate layer 101 , a silicon dioxide layer 102 , a lithium niobate thin film layer 103 and a silicon dioxide buffer layer 104 stacked in sequence, and the input waveguide 3 is embedded in the silicon dioxide buffer layer 104 .

[0035] Figure 4 for Figure 1 Schematic diagram of the electro-optic modulation chip with a three-axis modulator chip structure, as shown in Figure 4 As shown, from bottom to top, the lithium niobate thin film chip includes a stacked silicon substrate layer 101, a silicon dioxide layer 102, a lithium niobate thin film layer 103 and a silicon dioxide buffer layer 104. In this embodiment, the Y waveguide 81, the transmission waveguide 12 and the input waveguide 3 are all embedded in the silicon dioxide buffer layer 104.

[0036] Optionally, the input waveguide 3 is etched on the lithium niobate thin film layer 103 , and the silicon dioxide buffer layer 104 covers the input waveguide 3 .

[0037] In this embodiment, the Y waveguide 81, the transmission waveguide 12 and the input waveguide 3 are all etched on the lithium niobate thin film layer 103. The lithium niobate thin film layer 103 has a large refractive index difference. Therefore, the bending radius of the transmission waveguide 12 can be designed to be very small, which is conducive to the miniaturization design of the overall structure.

[0038] The present invention also provides a three-axis fiber optic gyroscope, including a light source and three fiber rings, and also includes the three-axis modulator chip structure described in any of the above embodiments, the light source is coupled to the input fiber 2 of the three-axis modulator chip structure, and the three fiber rings are coupled to the three output fiber groups 9 respectively.

[0039] The three-axis fiber optic gyroscope of the present invention utilizes waveguides to achieve coupling between the coupler and the input optical fiber 2, between the couplers, and between the coupler and the photodetector 6, thereby eliminating the need for optical fiber connection and the need for a fusion splicing process, thereby reducing costs and assembly difficulty and improving reliability. In addition, the coupler, Y-waveguide modulator 8, and photodetector 6 are all integrated into the electro-optic modulation chip 1, reducing the overall volume and meeting miniaturized application requirements.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-axis modulator chip structure, characterized in that: include: Electro-optical modulation chip (1); An input optical fiber (2), the input optical fiber (2) being fixedly connected to a side surface of the electro-optic modulation chip (1); An input waveguide (3), the input waveguide (3) being embedded in the top surface of the electro-optic modulation chip (1), and having a first end coupled to the input optical fiber (2); A one-to-three coupler (4), wherein a main port of the one-to-three coupler (4) is coupled to the second end of the input waveguide (3); Three first one-to-two couplers (5), wherein the first branch ports of the three first one-to-two couplers (5) are respectively coupled with the three branch ports of the one-to-three coupler (4) via transmission waveguides (12); Three photoelectric detectors (6), the three photoelectric detectors (6) being respectively fixedly connected to the side surfaces of the electro-optic modulation chip (1), and respectively coupled to the second branch ports of the three first one-to-two couplers (5) via transmission waveguides (12); Three second one-to-two couplers (7), the total ports of the three second one-to-two couplers (7) being coupled to the total ports of the three first one-to-two couplers (5) via transmission waveguides (12); Three groups of Y-waveguide modulators (8), each group of the Y-waveguide modulators (8) comprising a Y-waveguide (81) and a modulation electrode (82), the Y-waveguide (81) comprising a first branch arm and a second branch arm, the modulation electrode (82) being arranged on both sides of the extension direction of the first branch arm and the second branch arm, the first ends of the first branch arm and the second branch arm of each group of the Y-waveguide modulators (8) being respectively coupled to two branch ports of a second one-to-two coupler (7), the Y-waveguide modulator (8), the one-to-three coupler (4), the first one-to-two coupler (5) and the second one-to-two coupler (7) being respectively fixedly connected to the top surface of the electro-optical modulation chip (1); Three output optical fiber groups (9), the three output optical fiber groups (9) are respectively fixedly connected to the side of the electro-optic modulation chip (1), and are arranged in one-to-one correspondence with the three groups of Y-waveguide modulators (8), each of the output optical fiber groups (9) comprises two output optical fibers (91), and the two output optical fibers (91) are respectively coupled to the second ends of the first branch arm and the second branch arm of the corresponding Y-waveguide (81); A sealing cover, the sealing cover covers the top surface of the electro-optical modulation chip (1) and is fixedly connected to the electro-optical modulation chip (1).

2. The three-axis modulator chip structure according to claim 1, characterized in that: Also includes: A soldering pad (10), the soldering pad (10) being fixedly connected to the top surface of the electro-optical modulation chip (1) and electrically connected to the modulation electrode (82), and being used for connecting to an external power source.

3. The three-axis modulator chip structure according to claim 1 or 2, characterized in that: At least part of the transmission waveguide (12) is arranged in an arc shape.

4. The three-axis modulator chip structure according to claim 3, characterized in that: The three photoelectric detectors (6) are arranged on different sides of the electro-optic modulation chip (1).

5. The three-axis modulator chip structure according to claim 3, characterized in that: Absorption electrodes (11) are arranged on both sides of the transmission waveguide (12) in the extension direction.

6. The three-axis modulator chip structure according to claim 5, characterized in that: The absorption electrode (11) is made of gold.

7. The three-axis modulator chip structure according to claim 1 or 2, characterized in that: The electro-optic modulation chip (1) is a lithium niobate thin film chip.

8. The three-axis modulator chip structure according to claim 7, characterized in that: The lithium niobate thin film chip comprises a silicon substrate layer (101), a silicon dioxide layer (102), a lithium niobate thin film layer (103) and a silicon dioxide buffer layer (104) stacked in sequence, and the input waveguide (3) is embedded in the silicon dioxide buffer layer (104).

9. The three-axis modulator chip structure according to claim 8, characterized in that: The input waveguide (3) is etched on the lithium niobate film layer (103), and the silicon dioxide buffer layer (104) covers the input waveguide (3).

10. A three-axis fiber optic gyroscope, comprising a light source and three fiber optic rings, characterized in that: It also comprises the three-axis modulator chip structure according to any one of claims 1 to 9, wherein the light source is coupled to the input optical fiber (2) of the three-axis modulator chip structure, and the three optical fiber rings are coupled to the three output optical fiber groups (9) respectively.

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