Coupling device and method for photonic crystal fiber ring and lithium niobate modulator chip

Abstract

The invention discloses a photonic crystal fiber ring and lithium niobate modulator chip coupling device and method.The device comprises a chip bottom plate, a lens assembly, a prism assembly and two optical fiber collimator assemblies, the prism assembly is fixed to the chip bottom plate and used for deflecting an output light path of a lithium niobate modulator chip assembly, and the two optical fiber collimator assemblies are fixed to the lens assembly; and the distance between two output light paths of the lithium niobate modulator chip assembly is expanded to a preset distance for avoiding interference. Light beams output by the lithium niobate modulator chip assembly are converted into collimated light through the lens assembly, the collimated light is converged into the crystal optical fiber of the optical fiber collimator assembly and then enters the crystal optical fiber ring through the crystal optical fiber, by means of the space coupling scheme, the end face of the photonic crystal optical fiber does not need to be polished or subjected to hot melting, and the cost is reduced. Only simple cutting is carried out, blocking of air holes of the photonic crystal fiber by a traditional grinding scheme and damage of a hot melting method to the structure of the hollow fiber are avoided, and the integrity of the photonic crystal fiber is guaranteed.

Description

Technical Field

[0001] This application relates to the technical field of fiber optic loop and chip coupling, and particularly to a coupling device and method for a photonic crystal fiber optic loop and a lithium niobate modulator chip. Background Art

[0002] In the development process of fiber optic gyroscope systems, reducing polarization cross-coupling and back reflection in the sensitive optical path is a key requirement for improving system performance. To achieve this goal, a direct coupling scheme between the fiber optic loop and the modulator chip has been proposed in the industry.

[0003] Currently, solid-core polarization-maintaining fiber is commonly used in the industry. The core of this fiber is germanium-doped quartz, and the cladding contains a boron-doped stress region. However, in practical applications, this type of fiber has significant defects. Under different environmental conditions, its refractive index is unstable, and the stress region also changes, which in turn leads to changes in the birefringence characteristics, having an adverse impact on the accuracy and stability of the fiber optic gyroscope system.

[0004] To solve the above problems of solid-core polarization-maintaining fiber, photonic crystal fiber (hollow-core fiber) emerged as the times require. It is entirely composed of quartz, specifically consisting of SiO2 and air holes. Compared with traditional solid-core fibers, photonic crystal fibers have many advantages, such as low temperature sensitivity, low magnetic sensitivity, radiation resistance, and bending resistance. These characteristics enable the fiber optic gyroscope to achieve higher accuracy under the same volume conditions, or to achieve smaller volume and weight under the same accuracy requirements, thus becoming a new development trend in fiber optic gyroscope technology.

[0005] In terms of the coupling between the fiber and the lithium niobate modulator chip, conventional solid-core fibers mainly adopt the end-face coupling method, that is, grinding and polishing the fiber end-face and the chip end-face, and then using glue to bond the two together to achieve coupling. However, for photonic crystal fibers, due to the presence of air holes at their end-faces, using the conventional grinding scheme will cause the air holes to be blocked, thus affecting the fiber performance. To address this problem, two grinding and polishing schemes have emerged in the industry. One is to ventilate the photonic crystal fiber and grind it while ventilating to prevent the air holes from being blocked, as mentioned in CN103792619B, but this process is too complex and extremely difficult for mass production; the other is to thermally fuse a section of conventional solid-core fiber to the front end of the photonic crystal fiber and then grind the solid-core fiber, as described in CN106249353B. However, this method will cause certain damage to the hollow-core fiber structure, reducing the optimal performance of the product, and for photonic crystal fibers with different structures, the parameters of the fusion splicer need to be repeatedly adjusted.

[0006] In summary, the existing coupling methods for photonic crystal fibers and lithium niobate modulator chips have many deficiencies, and there is an urgent need for a new coupling device and method to solve these problems. Summary of the Invention

[0007] In order to solve the technical problems in the prior art, the present application provides a coupling device and method for a photonic crystal fiber loop and a lithium niobate modulator chip.

[0008] The coupling device and method for a photonic crystal fiber loop and a lithium niobate modulator chip provided by the present application adopt the following technical solutions: A coupling device for a photonic crystal fiber loop and a lithium niobate modulator chip, comprising: A chip base plate, on which a lithium niobate modulator chip assembly is fixed; A lens assembly, which is installed at the output end of the lithium niobate modulator chip assembly; A prism assembly, which is fixed on the chip base plate and is used to deflect an output optical path of the lithium niobate modulator chip assembly, so that the distance between the two output optical paths of the lithium niobate modulator chip assembly is expanded to a preset distance to avoid interference; and Two fiber collimator assemblies, both of the two fiber collimator assemblies are fixed on the chip base plate, the input ends of the two fiber collimator assemblies are respectively coupled with the two deflected output optical paths, and the output ends of the two fiber collimator assemblies are respectively connected with the two ends of the photonic crystal fiber loop.

[0009] Preferably, the coupling device for a photonic crystal fiber loop and a lithium niobate modulator chip further comprises a real-time calibration mechanism, and the real-time calibration mechanism comprises: A beam splitting prism, which is arranged between the prism assembly and the fiber collimator assembly and is used to divide a light beam into a transmitted light and a reflected light; An image sensor, which is used to receive the reflected light and generate a spot position signal; A processor, which is used to calculate the change in the refractive index of the prism according to the spot position signal and generate a compensation instruction; A piezoelectric adjustment module, which is used to adjust the tilt angle of the prism assembly according to the compensation instruction.

[0010] Preferably, the prism assembly comprises a fixing member and a deflecting prism, one end of the fixing member is hinged to the chip base plate, the other end of the fixing member is fixedly connected with the deflecting prism, and the deflecting prism is used to deflect an output optical path of the lithium niobate modulator chip assembly; The piezoelectric adjustment module comprises a piezoelectric stage and a connecting rod, the piezoelectric stage is fixed on the chip base plate, the output end of the piezoelectric stage is fixedly connected with one end of the connecting rod, and the other end of the connecting rod is hinged to the deflecting prism.

[0011] Preferably, the processor is communicatively connected with both the piezoelectric stage and the image sensor.

[0012] Preferably, the light intensity distribution ratio of the transmitted light to the reflected light is greater than 0.95.

[0013] Preferably, the fiber collimator group includes a collimator base plate, a glass tube, a lens, a capillary tube, and a photonic crystal fiber. The collimator base plate is used for bonding to the chip base plate. The glass tube is fixed to the collimator base plate. The lens is fixed inside the glass tube and is used to receive the deflected output optical path and converge the light beam of the output optical path into the photonic crystal fiber. The capillary tube is fixed inside the glass tube, and the photonic crystal fiber is inserted into the capillary tube. The output end of the photonic crystal fiber is connected to the corresponding end of the photonic crystal fiber loop.

[0014] Preferably, a glue solution is encapsulated between the photonic crystal fiber and the capillary tube.

[0015] The present invention also provides a coupling method for a photonic crystal fiber loop and a lithium niobate modulator chip, which is applicable to the coupling device of the photonic crystal fiber loop and the lithium niobate modulator chip, and includes the following steps: Output two optical signals with an initial distance less than a preset threshold through the lithium niobate modulator chip assembly; Collimate the two optical signals into parallel light beams by using a lens assembly; Deflect one of the collimated light beams through a prism assembly to expand the distance between the two light beams to a preset anti-interference distance; Input the two deflected collimated light beams into two fiber collimator assemblies respectively, and the two fiber collimator assemblies input the collimated light beams into both ends of the photonic crystal fiber loop respectively.

[0016] The present invention also provides a coupling method for a photonic crystal fiber loop and a lithium niobate modulator chip, which is applicable to the coupling device of the photonic crystal fiber loop and the lithium niobate modulator chip, and includes a real-time calibration method. The real-time calibration method includes: Reflect part of the light beam to an image sensor through a beam splitter prism to generate a spot position signal; Calculate the real-time refractive index of the deflection prism in the prism assembly and the real-time refractive index of the beam splitter prism according to the spot position signal; Based on the real-time refractive index of the deflection prism and the real-time refractive index of the beam splitter prism, dynamically adjust the tilt angle of the prism through a piezoelectric adjustment module so that the spot is projected within the input range of the fiber collimator assembly.

[0017] Preferably, according to the spot position signal and in combination with the refractive index-temperature relationship model of the prism, the current ambient temperature is determined, and the real-time refractive index of the beam splitting prism is determined according to the ambient temperature; according to the real-time refractive index of the deflection prism and the real-time refractive index of the beam splitting prism, the projection position of the spot on the plane where the end face of the photonic crystal fiber is located is obtained, and the tilt angle of the deflection prism is adjusted according to the projection position of the spot on the plane where the end face of the photonic crystal fiber is located.

[0018] In summary, the present application includes at least one of the following beneficial technical effects: 1. The light beam output by the lithium niobate modulator chip assembly is converted into collimated light through the lens assembly and converged into the crystal fiber of the fiber collimator assembly, and then enters the crystal fiber loop through the crystal fiber. By adopting this spatial coupling scheme, it is not necessary to polish or thermally fuse the end face of the photonic crystal fiber, only simple cutting is required, avoiding the blockage of the air holes of the photonic crystal fiber by the traditional grinding scheme and the damage to the structure of the hollow fiber by the thermal fusion method, ensuring the integrity of the photonic crystal fiber, so that the product can exert its optimal performance; 2. The real-time calibration mechanism can reflect part of the light beam to the image sensor through the beam splitting prism to obtain the spot position signal. The processor calculates the real-time refractive indices of the deflection prism and the beam splitting prism according to this signal, and then dynamically adjusts the tilt angle of the deflection prism through the piezoelectric adjustment module, so as to timely compensate for the influence brought by the refractive index change, ensure that the spot is always projected within the input range of the fiber collimator assembly, and effectively improve the stability of the optical signal coupling. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of a coupling device between a photonic crystal fiber loop and a lithium niobate modulator chip provided in Embodiment 1 of the present application; Figure 2 is Figure 1 a partial enlarged view of area A in Figure 3 is Figure 1 a schematic structural diagram of a fiber collimator assembly in Figure 4 is a schematic structural diagram of a coupling device between a photonic crystal fiber loop and a lithium niobate modulator chip provided in Embodiment 2 of the present application; Figure 5 is Figure 4 a partial enlarged view of area B in Description of reference numerals: 1. Chip base plate; 2. Lens assembly; 3. Prism assembly; 31. Fixing member; 32. Deflection prism; 4. Fiber collimator assembly; 41. Collimator base plate; 42. Glass tube; 43. Lens; 44. Capillary tube; 45. Photonic crystal fiber; 5. Lithium niobate modulator chip assembly; 6. Photonic crystal fiber loop; 7. Real-time calibration mechanism; 71. Beam splitting prism; 72. Image sensor; 73. Processor; 74. Piezoelectric adjustment module; 741. Piezoelectric stage; 742. Link rod. Detailed implementation manners

[0020] The following further describes the present application in conjunction with the attached Figures 1-5 drawings for a more detailed description.

[0021] Embodiment 1 Embodiment 1 of the present application discloses a coupling device for a photonic crystal fiber loop and a lithium niobate modulator chip. Referring to Figures 1-3 , the coupling device for a photonic crystal fiber loop and a lithium niobate modulator chip includes a chip base plate 1, a lens assembly 2, a prism assembly 3, and two fiber collimator assemblies 4.

[0022] The chip base plate 1 is used to fix the lithium niobate modulator chip assembly 5; the lens assembly 2 is installed at the output end of the lithium niobate modulator chip assembly 5, and the prism assembly 3 is fixed on the chip base plate 1 and is used to deflect one output optical path of the lithium niobate modulator chip assembly 5, so that the distance between the two output optical paths of the lithium niobate modulator chip assembly 5 is expanded to a preset distance to avoid interference; the two fiber collimator assemblies 4 are both fixed on the chip base plate 1, the input ends of the two fiber collimator assemblies 4 are respectively coupled to the two output optical paths after deflection, and the output ends of the two fiber collimator assemblies 4 are respectively connected to the two ends of the photonic crystal fiber loop 6.

[0023] The usage method of the coupling device for a photonic crystal fiber loop and a lithium niobate modulator chip in Embodiment 1 includes the following steps: Output two optical signals with an initial distance less than a preset threshold through the lithium niobate modulator chip assembly 5; Collimate the two optical signals into parallel light beams by using the lens assembly 2; Deflect one of the collimated light beams through the prism assembly 3 so that the distance between the two light beams is expanded to a preset anti-interference distance; Input the two deflected collimated light beams into the two fiber collimator assemblies 4 respectively, and the two fiber collimator assemblies 4 input the collimated light beams into the two ends of the photonic crystal fiber loop 6 respectively.

[0024] The technical effects of the above technical solution are as follows: The light beam output from the lithium niobate modulator chip assembly 5 is converted into collimated light through the lens assembly 2 and converges into the photonic crystal fiber 45 of the fiber collimator assembly 4, and then enters the photonic crystal fiber loop 6 through the photonic crystal fiber 45. By adopting this spatial coupling scheme, it is not necessary to polish or thermally fuse the end face of the photonic crystal fiber 45, but only simple cutting is required, avoiding the blockage of the air holes of the photonic crystal fiber 45 by the traditional grinding scheme and the damage to the hollow fiber structure by the thermal fusion method, ensuring the integrity of the photonic crystal fiber 45, so that the product can exhibit the optimal performance.

[0025] In one embodiment, please refer to Figures 1-3 , the fiber collimator group includes a collimator base plate 41, a glass tube 42, a lens 43, a capillary tube 44 and a photonic crystal fiber 45. The collimator base plate 41 is used for bonding to the chip base plate 1. The glass tube 42 is fixed to the collimator base plate 41. The lens 43 is fixed in the glass tube 42 and is used to receive the deflected output optical path and converge the light beam of the output optical path into the photonic crystal fiber 45. The capillary tube 44 is fixed in the glass tube 42, and the photonic crystal fiber 45 is inserted into the capillary tube 44, and the output end of the photonic crystal fiber 45 is connected to the corresponding end of the photonic crystal fiber loop 6.

[0026] In this embodiment, the function of the lens 43 is to receive the deflected output optical path and converge the light beam into the photonic crystal fiber 45. By reasonably designing the parameters of the lens 43, efficient convergence of the light beam can be achieved, the coupling efficiency of the optical signal can be improved, and the loss of the optical signal during transmission can be reduced, thereby enhancing the transmission quality and intensity of the optical signal.

[0027] In one embodiment, please refer to Figures 1-3 , there is glue liquid encapsulated between the photonic crystal fiber 45 and the capillary tube 44.

[0028] Embodiment 2 Please refer to Figures 4-5 , the difference between Embodiment 2 and Embodiment 1 is that in Embodiment 2, the photonic crystal fiber loop and the lithium niobate modulator chip coupling device further include a real-time calibration mechanism 7, and the real-time calibration mechanism 7 includes a beam splitting prism 71, an image sensor 72, a processor 73 and a piezoelectric adjustment module 74.

[0029] The beam splitting prism 71 is disposed between the prism assembly 3 and the fiber collimator assembly 4 for splitting the light beam into transmitted light and reflected light; the image sensor 72 is used to receive the reflected light and generate a spot position signal; the processor 73 is used to calculate the change in the refractive index of the prism according to the spot position signal and generate a compensation instruction; the piezoelectric adjustment module 74 is used to adjust the tilt angle of the prism assembly 3 according to the compensation instruction.

[0030] In one embodiment, please refer to Figures 4-5 , the prism assembly 3 includes a fixing member 31 and a deflecting prism 32. One end of the fixing member 31 is hinged to the chip base plate 1, and the other end of the fixing member 31 is fixedly connected to the deflecting prism 32. The deflecting prism 32 is used to deflect an output optical path of the lithium niobate modulator chip assembly 5; the piezoelectric adjustment module 74 includes a piezoelectric stage 741 and a connecting rod 742. The piezoelectric stage 741 is fixed to the chip base plate 1, the output end of the piezoelectric stage 741 is fixedly connected to one end of the connecting rod 742, and the other end of the connecting rod 742 is hinged to the deflecting prism 32.

[0031] In this embodiment, the piezoelectric stage 741 is a driving device based on the piezoelectric effect. When a voltage is applied to the electrodes of the piezoelectric stage 741, the piezoelectric material will produce a tiny deformation, thereby outputting a certain displacement. By precisely controlling the magnitude and direction of the voltage applied to the piezoelectric stage 741, the magnitude and direction of the displacement output by the piezoelectric stage 741 can be accurately controlled. One end of the connecting rod 742 is fixedly connected to the output end of the piezoelectric stage 741, and the other end is hinged to the deflecting prism 32. When the piezoelectric stage 741 generates a displacement, the connecting rod 742 will convert the displacement of the piezoelectric stage 741 into a force acting on the deflecting prism 32. Since the deflecting prism 32 is hinged to the chip base plate 1 through one end of the fixing member 31, under the action of the connecting rod 742, the deflecting prism 32 will rotate around the hinge point, thereby realizing the adjustment of the tilt angle.

[0032] The piezoelectric stage 741 can achieve a very small displacement output, and its displacement accuracy can reach the micron or even nanometer level. By transmitting this tiny displacement to the deflecting prism 32 through the connecting rod 742, the tilt angle of the deflecting prism 32 can be accurately controlled. During the coupling process of the photonic crystal fiber loop and the lithium niobate modulator chip, even a tiny angle change may have a significant impact on the coupling efficiency and quality of the optical signal. The precise adjustment ability of the piezoelectric stage 741 and the connecting rod 742 can ensure that the tilt angle of the deflecting prism 32 is adjusted to the optimal state, so that the optical signal can be accurately projected onto the input end of the fiber collimator assembly 4, improving the accuracy of the optical path adjustment.

[0033] In one embodiment, please refer to Figures 4-5, the processor 73 is communicatively connected to both the piezoelectric stage 741 and the image sensor 72.

[0034] In one embodiment, refer to Figures 4-5 , the light intensity distribution ratio of the transmitted light to the reflected light is greater than 0.95. In this embodiment, the higher transmitted light intensity ensures that there is sufficient intensity of the optical signal entering the photonic crystal fiber 45, thereby enhancing the transmission ability of the optical signal in the optical fiber. A stronger optical signal can better resist various interferences and attenuations during the transmission process, ensuring that the optical signal can be accurately and stably transmitted to the corresponding end of the photonic crystal fiber loop 6, improving the transmission quality of the optical signal.

[0035] The real-time calibration method for the coupling device between the photonic crystal fiber loop and the lithium niobate modulator chip in Embodiment 2 includes the following steps: Reflect part of the light beam through the beam splitter prism 71 to the image sensor 72 to generate a spot position signal; Calculate the real-time refractive index of the deflection prism 32 and the real-time refractive index of the beam splitter prism 71 in the prism assembly 3 according to the spot position signal; Based on the real-time refractive index of the deflection prism 32 and the real-time refractive index of the beam splitter prism 71, dynamically adjust the tilt angle of the deflection prism 32 through the piezoelectric adjustment module 74 so that the spot is projected within the input range of the fiber collimator assembly 4.

[0036] In practical applications, changes in environmental factors such as temperature and humidity will cause changes in the refractive indices of the deflection prism 32 and the beam splitter prism 71, thereby causing the spot position to shift. The real-time calibration mechanism 7 can reflect part of the light beam to the image sensor 72 through the beam splitter prism 71 to obtain the spot position signal. The processor 73 calculates the real-time refractive indices of the deflection prism 32 and the beam splitter prism 71 according to this signal, and then dynamically adjusts the tilt angle of the deflection prism 32 through the piezoelectric adjustment module 74, thereby compensating in time for the influence brought by the refractive index change, ensuring that the spot is always projected within the input range of the fiber collimator assembly 4, and effectively improving the stability of optical signal coupling.

[0037] In one embodiment, refer to Figures 4-5 , according to the spot position signal, in combination with the refractive index-temperature relationship model of the deflection prism 32, determine the current ambient temperature, and determine the real-time refractive index of the beam splitter prism 71 according to the ambient temperature; according to the real-time refractive index of the deflection prism 32 and the real-time refractive index of the beam splitter prism 71, obtain the projection position of the spot on the plane where the end face of the photonic crystal fiber 45 is located, and adjust the tilt angle of the deflection prism 32 according to the projection position of the spot on the plane where the end face of the photonic crystal fiber 45 is located.

[0038] The technical effects of the technical solution provided by this application include: (1)The light beam output by the lithium niobate modulator chip assembly 5 is converted into collimated light through the lens assembly 2 and converged into the photonic crystal fiber 45 of the fiber collimator assembly 4, and then enters the photonic crystal fiber loop 6 through the photonic crystal fiber 45. By adopting this spatial coupling scheme, it is not necessary to polish or thermally fuse the end face of the photonic crystal fiber 45, but only simple cutting is required, avoiding the blockage of the air holes of the photonic crystal fiber 45 by the traditional grinding scheme and the damage to the structure of the hollow fiber by the thermal fusion method, ensuring the integrity of the photonic crystal fiber 45, so that the product can exhibit the optimal performance.

[0039] (2)The real-time calibration mechanism 7 can reflect part of the light beam to the image sensor 72 through the beam splitting prism 71 to obtain the spot position signal. The processor 73 calculates the real-time refractive indices of the deflection prism 32 and the beam splitting prism 71 according to this signal, and then dynamically adjusts the tilt angle of the deflection prism 32 through the piezoelectric adjustment module 74, so as to timely compensate for the influence brought by the refractive index change, ensure that the spot is always projected within the input range of the fiber collimator assembly 4, and effectively improve the stability of the optical signal coupling.

[0040] The specific embodiments of the present application described above do not constitute a limitation on the protection scope of the present application. Any other corresponding changes and deformations made according to the technical concept of the present application shall be included in the protection scope of the present application.

Claims

1. A coupling device for a photonic crystal fiber ring and a lithium niobate modulator chip, characterized in that: include: A chip base plate (1) on which a lithium niobate modulator chip assembly (5) is fixed; A lens assembly (2) mounted on the output end of the lithium niobate modulator chip assembly (5); a prism assembly (3) fixed on the chip base plate (1) and used for deflecting an output light path of the lithium niobate modulator chip assembly (5) so as to expand the distance between the two output light paths of the lithium niobate modulator chip assembly (5) to a preset distance to avoid interference; as well as Two optical fiber collimator assemblies (4), both of which are fixed to the chip base plate (1), the input ends of the two optical fiber collimator assemblies (4) are respectively coupled with the two output light paths after deflection, and the output ends of the two optical fiber collimator assemblies (4) are respectively connected to the two ends of the photonic crystal optical fiber ring (6).

2. The device for coupling a photonic crystal fiber ring and a lithium niobate modulator chip according to claim 1, characterized in that: It also includes a real-time calibration mechanism (7), wherein the real-time calibration mechanism (7) includes: A beam splitting prism (71) is disposed between the prism assembly (3) and the optical fiber collimator assembly (4) and is used to split the light beam into transmitted light and reflected light; An image sensor (72), used for receiving the reflected light and generating a light spot position signal; A processor (73), configured to calculate a change in the refractive index of the prism according to the light spot position signal, and generate a compensation instruction; The piezoelectric adjustment module (74) is used to adjust the tilt angle of the prism assembly (3) according to the compensation instruction.

3. The device for coupling a photonic crystal fiber ring and a lithium niobate modulator chip according to claim 2, characterized in that: The prism assembly (3) comprises a fixing member (31) and a deflection prism (32), one end of the fixing member (31) is hinged to the chip base plate (1), and the other end of the fixing member (31) is fixedly connected to the deflection prism (32), and the deflection prism (32) is used to deflect an output light path of the lithium niobate modulator chip assembly (5); The piezoelectric adjustment module (74) comprises a piezoelectric station (741) and a connecting rod (742); the piezoelectric station (741) is fixed to the chip base plate (1); the output end of the piezoelectric station (741) is fixedly connected to one end of the connecting rod (742); and the other end of the connecting rod (742) is hinged to the deflection prism (32).

4. The device for coupling a photonic crystal fiber ring and a lithium niobate modulator chip according to claim 3, characterized in that: The processor (73) is communicatively connected to the piezoelectric station (741) and the image sensor (72).

5. The device for coupling a photonic crystal fiber ring and a lithium niobate modulator chip according to claim 2, characterized in that: The light intensity distribution ratio of the transmitted light to the reflected light is greater than 0.

95.

6. The device for coupling a photonic crystal fiber ring and a lithium niobate modulator chip according to claim 1, characterized in that: The optical fiber collimator group comprises a collimator base plate (41), a glass tube (42), a lens (43), a capillary tube (44), and a photonic crystal optical fiber (45); the collimator base plate (41) is used for bonding to the chip base plate (1); the glass tube (42) is fixed to the collimator base plate (41); the lens (43) is fixed in the glass tube (42) and is used for receiving the output light path after deflection and converging the light beam of the output light path into the photonic crystal optical fiber (45); the capillary tube (44) is fixed in the glass tube (42); the photonic crystal optical fiber (45) is plugged in the capillary tube (44); and the output end of the photonic crystal optical fiber (45) is connected to the corresponding end of the photonic crystal optical fiber ring (6).

7. The device for coupling a photonic crystal fiber ring and a lithium niobate modulator chip according to claim 6, characterized in that: Glue is encapsulated between the photonic crystal optical fiber (45) and the capillary tube (44).

8. A method for coupling a photonic crystal fiber ring with a lithium niobate modulator chip, characterized in that: The device is applicable to the photonic crystal fiber ring and lithium niobate modulator chip coupling device as claimed in any one of claims 1 to 7, and comprises the following steps: Outputting two optical signals with an initial spacing less than a preset threshold value through a lithium niobate modulator chip component (5); Using a lens assembly (2) to collimate the two optical signals into parallel light beams; Deflecting one of the collimated light beams by means of a prism assembly (3) so that the distance between the two light beams is expanded to a preset anti-interference distance; The two deflected collimated light beams are respectively input into two optical fiber collimator components (4), and the two optical fiber collimator components (4) respectively input the collimated light beams into two ends of a photonic crystal optical fiber ring (6).

9. A method for coupling a photonic crystal fiber ring with a lithium niobate modulator chip, characterized in that: The device is applicable to the coupling device of the photonic crystal fiber ring and the lithium niobate modulator chip as claimed in claim 3, and includes a real-time calibration method, wherein the real-time calibration method includes: Reflecting part of the light beam to the image sensor (72) through a beam splitting prism (71) to generate a light spot position signal; Calculating the real-time refractive index of the deflection prism (32) and the real-time refractive index of the beam splitting prism (71) in the prism assembly (3) according to the light spot position signal; Based on the real-time refractive index of the deflection prism (32) and the real-time refractive index of the beam splitting prism (71), the inclination angle of the deflection prism (32) is dynamically adjusted through a piezoelectric adjustment module (74) so ​​that the light spot is projected into the input end range of the optical fiber collimator component (4).

10. The method for coupling a photonic crystal fiber ring with a lithium niobate modulator chip according to claim 9, characterized in that: Determining the current ambient temperature based on the light spot position signal and in combination with a refractive index-temperature relationship model of the deflection prism (32), and determining the real-time refractive index of the beam splitting prism (71) based on the ambient temperature; The projection position of the light spot on the plane where the end face of the photonic crystal optical fiber (45) is located is obtained according to the real-time refractive index of the deflection prism (32) and the real-time refractive index of the beam splitting prism (71), and the tilt angle of the deflection prism (32) is adjusted according to the projection position of the light spot on the plane where the end face of the photonic crystal optical fiber (45) is located.

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