CN115683081A - Sensitive ring coupling structure and coupling method - Google Patents

Abstract

The application relates to a sensitive ring coupling structure and coupling method, which includes an optical waveguide chip fiber ring assembly and an input end pigtail assembly, the optical waveguide chip includes a chip substrate and a Y-shaped optical waveguide formed on the chip substrate, The Y-shaped optical waveguide includes an input end, a first branch and a second branch, and the fiber ring assembly includes a first substrate and a fiber ring fixed to the first substrate; the fiber ring includes a first input fiber and a second fiber ring. Two input optical fibers, the first branch is connected to the first input optical fiber through curing glue, and the second branch is connected to the second input optical fiber through curing glue. The pigtail assembly includes a second substrate and a second optical fiber fixed to the second substrate, the thickness of the second substrate is the same as that of the first substrate, and the input end of the second optical fiber and the Y-shaped optical waveguide Connected by curing glue.

Description

A sensitive ring coupling structure and coupling method

technical field

The present application relates to the technical field of optical fiber sensing, in particular to a sensitive ring coupling structure and coupling method.

Background technique

Fiber optic gyroscope is an all-solid-state angular rate sensing instrument, which has the advantages of fast start-up, large accuracy coverage, high reliability and low cost, and has become a mainstream instrument in the fields of inertial navigation, guidance and measurement. High-precision fiber optic gyroscopes generally use high-birefringence polarization-maintaining fiber rings, broadband light sources and Y-waveguide device solutions. The polarization-maintaining optical fiber ring is the sensing part, which is fused and coupled with the two output pigtails of the Y-waveguide device to form a closed loop to sense the rotation information of the system relative to the inertial space.

In the related art, in order to realize the direct butt coupling between the Y waveguide and the fiber ring, a straight waveguide is provided in the optical waveguide chip on both sides of the Y waveguide as an auxiliary waveguide, by detecting the coupling quality between the pigtail and the straight waveguide. Reflects the coupling quality between the Y waveguide and the fiber ring. However, this solution has the following problems: First, the quality of fiber coupling is heavily dependent on the processing technology of the straight waveguides on both sides of the working waveguide and the accompanying optical fiber, and secondly, there is a difference in the axial consistency between the accompanying optical fiber and the working optical fiber. If there is a processing deviation between the straight waveguide and the accompanying optical fiber, the coupling quality of the straight waveguide cannot accurately reflect the coupling quality of the fiber ring and the Y waveguide.

Contents of the invention

In order to realize the precise coupling of the polarization-maintaining optical fiber ring and the optical waveguide chip, the present application provides a sensitive ring coupling structure and coupling method.

A sensitive ring coupling structure and coupling method provided in this application adopts the following technical scheme:

A sensitive ring coupling structure, wherein the sensitive ring coupling structure includes an optical waveguide chip, an optical fiber ring assembly, and an input end pigtail assembly, and the optical waveguide chip includes a chip substrate and a Y-shaped optical fiber formed on the chip substrate. Waveguide, the Y-shaped optical waveguide includes an input end, a first branch and a second branch, the fiber ring assembly includes a first substrate and a fiber ring fixed to the first substrate, the thickness of the first substrate is the same as The thickness of the chip substrate is not the same; the optical fiber ring includes a first input optical fiber and a second input optical fiber, the first branch and the first input optical fiber are connected by curing glue, and the second branch and the second input optical fiber are connected by curing glue connection. The pigtail assembly includes a second substrate and a second optical fiber fixed to the second substrate, the thickness of the second substrate is the same as that of the first substrate, and the input end of the second optical fiber and the Y-shaped optical waveguide Connected by curing glue.

In one embodiment of the present invention, the first substrate is provided with two installation grooves, the optical fiber ring is wound by a polarization-maintaining optical fiber, and the center of the panda eye of the polarization-maintaining optical fiber is aligned with the center of the fiber core. The connecting line at the center is perpendicular or parallel to the center line of the installation groove; the second substrate is provided with an installation groove, the second optical fiber is a polarization maintaining optical fiber, and the center of the panda eye of the second optical fiber is aligned with the fiber The line connecting the center of the core is perpendicular or parallel to the center line of the installation slot; vertical or parallel.

In one of the embodiments of the present invention, the sensitive ring coupling structure further includes a broadband light source, an optical power meter, and a coupler; the input ends of the coupler are connected to the broadband light source and the optical power meter respectively, and the The output end of the coupler is connected to one end of the second optical fiber, and the incident end of the Y-shaped optical waveguide is connected to the other end of the second optical fiber.

In one embodiment of the present invention, opposite side surfaces of the chip substrate are respectively fixed to the first substrate and the second substrate.

In one of the embodiments of the present invention, the angle between the side surface of the Y-shaped optical waveguide and its own longitudinal section is 6-12°, and the included angle between the side surface of the optical fiber ring assembly and its own longitudinal section is 10-15°.

The present application also relates to a coupling method of a sensitive ring coupling structure, wherein the coupling method includes:

An optical waveguide chip, an optical fiber ring assembly, and a pigtail assembly are provided, the optical waveguide chip includes a chip substrate and a Y-shaped optical waveguide formed on the chip substrate, and the Y-shaped optical waveguide includes an input end, a first branch and a second branch. Two branches, the fiber ring assembly includes a first substrate and a fiber ring fixed to the first substrate; the fiber ring includes a first input fiber and a second input fiber;

Aligning the first input fiber and the first branch, aligning the second input fiber and the second branch, coupling the optical signal of the first branch to the first input fiber, and coupling the optical signal of the second branch to the second input fiber; as well as

Applying curing glue to the bonding surface of the first branch and the first input optical fiber, and applying curing glue to the bonding surface of the second branch and the second input optical fiber; and

The curing glue is cured, so that the first branch is connected with the first input optical fiber through the curing glue, and the second branch is connected with the second input optical fiber through the curing glue.

The pigtail assembly includes a second substrate and a second optical fiber fixed to the second substrate, the thickness of the second substrate is the same as that of the first substrate, and the pigtail assembly is aligned with the input of the Y-shaped optical waveguide end,

Apply curing glue to the joint surface of the pigtail assembly and the input end of the Y waveguide, and connect the second optical fiber to the input end of the Y-shaped optical waveguide through curing glue.

In one embodiment of the present invention, the first input fiber is aligned with the first branch, the second input fiber is aligned with the second branch, the input end fiber pigtail assembly and the input end of the Y-shaped waveguide are aligned, so that the input end tail The optical signal of the fiber assembly is input to the input end of the Y-shaped waveguide, the optical signal of the first branch is coupled to the first input optical fiber, and the method for coupling the optical signal of the second branch to the second input optical fiber includes:

providing a broadband light source, an optical power meter, and a coupler; making the input ends of the coupler electrically connected to the broadband light source and the optical power meter respectively, and aligning the output end of the coupler with the second optical fiber;

The wide-spectrum light source emits light beams, and the light beams emitted by the wide-spectrum light source are filtered by the coupler, then transmitted through the pigtail assembly, the optical waveguide chip and the optical fiber ring assembly, and generate beam splitting and combining in the optical waveguide chip. After the beam, it reaches the optical power meter through the coupler, and the power is detected by the optical power meter; and

The degree of alignment coupling between the first branch and the first input optical fiber, and between the second branch and the second input optical fiber is judged according to the power.

In one embodiment of the present invention, opposite side surfaces of the chip substrate are respectively fixed to the first substrate and the second substrate.

In one embodiment of the present invention, the angle between the side surface of the Y-shaped optical waveguide and its own longitudinal section is 6-12°, and the included angle between the side surface of the optical fiber ring assembly and its own longitudinal section 10-15°.

In one embodiment of the present invention, while providing a broadband light source, an optical power meter, and a coupler, it also includes providing two clamps and two six-dimensional electric tables, and using two clamps to clamp the pigtail assembly and the optical fiber respectively ring assembly, and set each fixture on one of the six-dimensional electric stages, set the angle adjustment range and step diameter of the six-dimensional electric stage, and gradually adjust the climbing angle of the six-dimensional electric stage according to the step diameter to adjust the optical waveguide The alignment coupling degree of the chip and the fiber ring assembly, and record the power detected by the optical power meter corresponding to each step value, record the power corresponding to all step values, and compare the optical waveguide chip and the fiber ring when the maximum power is detected. Components are fixed.

In summary, the present application includes at least one of the following beneficial technical effects:

1. Compared with related technologies, the optical waveguide chip included in the sensitive ring structure provided by the application includes a chip substrate and a Y-shaped optical waveguide formed on the chip substrate, and the Y-shaped optical waveguide includes an input end, a first A branch and a second branch, the optical fiber ring includes a first input fiber and a second input fiber, the first branch and the first input fiber are connected by curing glue, and the second branch and the second input fiber are connected by curing glue Connecting, the pigtail assembly at the input end is connected with the input end of the Y-shaped optical waveguide through curing glue. That is to say, the pigtail assembly at the input end, the fiber ring assembly and the optical waveguide chip are bonded and fixed by curing glue to form a direct-coupled sensitive ring coupling structure, thereby avoiding polarization cross-coupling and back reflection due to unsatisfactory fusion splicing other noise effects.

2. The included angle between the side surface of the Y-shaped optical waveguide of the present application and the side surface of the Y-shaped optical waveguide and its longitudinal section direction is 6-12°, and the angle between the side surface of the optical fiber ring assembly and its own longitudinal section is The angle between them is 10-15°; when the pigtail assembly is matched with the Y-shaped optical waveguide, the plane where the pigtail assembly is located and the plane where the Y-shaped optical waveguide is located form a certain slight inclination, and the optical fiber ring assembly and the Y-shaped optical waveguide When the optical waveguide is matched, the optical fiber ring component and the plane where the Y-shaped optical waveguide is located form a certain slight inclination, so that the back reflection loss can be reduced at both the input and output ends of the optical waveguide.

3. The first substrate of the present application can fix the two optical fibers of the fiber ring, and only one six-dimensional motorized stage is needed for the first substrate when performing optical power detection, thereby simplifying the calibration process.

4. The optical waveguide chip, the input end fiber optic assembly and the fiber ring assembly included in the sensitive ring structure of this application are coupled and calibrated by a six-dimensional electric stage, and multiple optical power meters are detected at different positions and different pitch angles. Power, when the power is maximum, it means that the optical fiber ring component and the optical waveguide chip have achieved precise alignment. At this time, drip the Appropriate amount of curing glue, after it evenly fills the end face of the optical waveguide chip and fiber ring assembly, optical waveguide chip and pigtail assembly, use ultraviolet curing light source to irradiate the coupling point, realize the firm bonding and fixing of the three, and form a sensitive direct coupling ring.

Description of drawings

Fig. 1 is a structural schematic diagram of a sensitive ring coupling structure provided by the present application;

Fig. 2 is a schematic structural view of the optical fiber ring assembly provided in Fig. 1;

Fig. 3 is a schematic diagram of coupling alignment of the sensitive ring coupling structure provided in Fig. 1;

FIG. 4 is a structural schematic diagram of another perspective of the sensitive ring coupling structure provided in FIG.

Description of reference numerals: 100, sensitive ring coupling structure; 1, optical waveguide chip; 2, optical fiber ring assembly; 3, pigtail assembly; 11, chip substrate; 12, Y-shaped optical waveguide; 120, incident end; 121, 122, the first branch; 124, the second branch; 20, the first substrate; 22, the installation groove; 24, the fiber ring; 240, the first input fiber; 242, the second input fiber; 4, wide spectrum Light source; 5, optical power meter; 6, coupler; 30, second substrate; 32, second optical fiber; 245, polarization maintaining optical fiber; 246, panda eye; 248, fiber core; B, longitudinal section.

Detailed ways

Please refer to Figures 1-2, Figure 1 is a sensitive ring coupling structure 100 provided by the present application, wherein the sensitive ring coupling structure 100 includes an optical waveguide chip 1, an optical fiber ring assembly 2 and a pigtail assembly 3, the optical The waveguide chip 1 includes a chip substrate 11 and a Y-shaped optical waveguide 12 formed on the chip substrate 11 .

The optical waveguide chip 1 is based on an X-cut Y-transfer lithium niobate wafer as the substrate material. The optical waveguide chip 1 has a single polarization characteristic, that is, it can only transmit TE modes whose electric vector direction is parallel to the Z-cut direction of the lithium niobate wafer. The chip substrate 11 forms the Y-shaped optical waveguide and the push-pull modulation electrode through processes such as photolithography, annealing proton exchange, evaporation, and electroplating. The Y-shaped optical waveguide 12 includes a first branch 122 and a second branch 124, the fiber ring assembly 2 includes a first substrate 20 and a fiber ring 24 fixed to the first substrate 20, the first substrate 20 The thickness is different from that of the chip substrate 11; the two input optical fibers included in the optical fiber ring 24 are all fixed on the first substrate 20, that is, the two input optical fibers include the first input optical fiber 240 and the second input optical fiber respectively. Input optical fiber 242, the distance between the first input optical fiber 240 and the second input optical fiber 242 and the distance difference between the first branch and the second branch are less than or equal to 0.5um, preferably equal; the first branch 122 The ends of the second branch 124 are aligned with the ends of the second input optical fiber 242 and then connected by curing glue.

The pigtail assembly 3 includes a second substrate 30 and a second optical fiber 32 fixed to the second substrate 30 . The pigtail assembly 3 is disposed on the opposite end surface of the optical waveguide chip 1 opposite to the optical fiber ring assembly 2 . The second optical fiber 32 is connected to one end of the Y-shaped optical waveguide 12 through curing glue.

Compared with related technologies, the sensitive ring coupling structure 100 provided by the present application includes an optical waveguide chip 1, and the optical waveguide chip 1 includes a chip substrate 11 and a Y-shaped optical waveguide 12 formed on the chip substrate 11, and the Y-shaped optical waveguide 12 includes a first branch 122 and a second branch 124, and the optical fiber ring 24 includes a first input fiber 240 and a second input fiber 242, and the distance between the first input fiber 240 and the second input fiber 242 is the same as that of the first branch 122 and the distance difference between the second branch 124≤0.5um; the first branch 122 is connected to the first input optical fiber 240 through curing glue, and the second branch 124 is connected to the second input optical fiber 242 through curing glue, That is to say, the optical fiber ring assembly 2 and the optical waveguide chip 1 are bonded and fixed by curing glue, the pigtail assembly 3 and the optical waveguide chip 1 are bonded and fixed by curing glue, and finally a sensitive ring coupling structure 100 for direct coupling is formed, thereby avoiding Noise effects such as polarization cross-coupling and back reflections due to suboptimal splices.

In one embodiment of the present invention, the first substrate 20 is provided with two installation grooves 22, the optical fiber ring 24 is wound by a polarization maintaining optical fiber 245, and the panda eye 246 of the polarization maintaining optical fiber 245 A line connecting the center of the fiber core 248 and the center of the fiber core 248 is perpendicular or parallel to the center line of the installation slot 22 . The installation groove 22 is V-shaped or U-shaped, and in this embodiment, the installation groove 22 is V-shaped. In this embodiment, the outer cladding of the polarization-maintaining optical fiber 245 is removed, so that the core 248 is placed in the installation groove 22, pressed by the presser part, and bonded by an adhesive, and finally Surfaces are ground and polished to the required precision.

In this embodiment, the second substrate 30 is provided with a mounting groove, the second optical fiber 32 is a polarization-maintaining fiber, and the second optical fiber 32 is located in the mounting groove of the second substrate 30. The second The connecting line between the center of the panda eye of the optical fiber 32 and the center of the fiber core is perpendicular or parallel to the center line of the installation groove; The connecting line between the center and the center of the fiber core is perpendicular or parallel to the center line of the installation groove, and the center of the panda eye of the second optical fiber 32 installed in the installation groove of the second substrate 30 is aligned with the center line of the second optical fiber 32. The line connecting the center of the fiber core is perpendicular or parallel to the center line of the installation slot, so that the polarization crosstalk between the two polarization-maintaining fibers of the fiber ring assembly 2 can be reduced. Since the polarization crosstalk characterizes the polarization performance of the polarization maintaining fiber, the smaller the polarization crosstalk of the polarization maintaining fiber, the stronger the ability of the polarization maintaining fiber to maintain the polarization state of the incident light. The better the polarization maintaining performance of the polarizing fiber is. The worst value of polarization crosstalk between two polarization-maintaining fibers of a sensitive ring coupling structure 100 provided by the present application is better than -30dB. The worst value of polarization crosstalk between polarization-maintaining fibers is also -30dB. Compared with the prior art, the polarization crosstalk of a sensitive ring coupling structure 100 provided by this application can reach the level of the prior art, but this application provides Since the sensitive ring coupling structure of the present invention does not require a straight waveguide, the manufacturing process is simpler.

In one of the embodiments of the present invention, the sensitive ring coupling structure 100 also includes a broadband light source 4, an optical power meter 5, and a coupler 6; the input end of the coupler 6 is connected to the broadband light source 4 and the optical power meter respectively. The meter 5 is connected, the output end of the coupler 6 is connected to one end of the second optical fiber 32 , and the incident end 120 of the Y-shaped optical waveguide 12 is connected to the other end of the second optical fiber 32 .

In one embodiment of the present invention, opposite sides of the chip substrate 11 are respectively fixed to the first substrate 20 and the second substrate 30 .

Please refer to Fig. 4, in one of the embodiments of the present invention, the inclination angle of the end face of the first branch 122 and the end face of the second branch 124 of the Y-shaped optical waveguide 12 and the vertical direction is 6-12°, preferably It is 8 °, and the inclination angle between the end face of the optical fiber ring 24 and the vertical direction is 10-15 °, preferably 12 °, so that the Y-shaped optical waveguide and the end face of the optical fiber ring 24 have an angle difference to avoid back reflection, At the same time, the coupling efficiency is not reduced. In the present application, the end face of the optical fiber ring 24 is polished at a predetermined angle, and the end face of the optical fiber ring 24 and the end face of the first branch 122 of the Y-shaped optical waveguide 12 are aligned according to the law of refraction. and the end face of the second branch 124 .

Please refer to FIG. 3, the present application also relates to a coupling method of a sensitive ring coupling structure 100, wherein the coupling method includes:

S1: Provide an optical waveguide chip 1 and an optical fiber ring assembly 2, the optical waveguide chip 1 includes a chip substrate 11 and a Y-shaped optical waveguide 12 formed on the chip substrate 11, and the Y-shaped optical waveguide 12 includes a first branch 122 and a second branch 124, the fiber ring assembly 2 includes a first substrate 20 and a fiber ring 24 fixed to the first substrate 20; the fiber ring 24 includes a first input fiber 240 and a second input fiber 242.

The fiber optic ring assembly 2 can be assembled in the following manner. Firstly, a first substrate 20 is provided, and two parallel installation grooves 22 are arranged in the first substrate 20 .

An optical fiber ring 24 is provided, wherein the two optical fibers of the optical fiber ring 24 are polarization maintaining optical fibers 245 .

The polarization-maintaining optical fiber 245 is arranged in the installation groove 22, and the position of the polarization-maintaining optical fiber 245 in the installation groove 22 is photographed by an image pickup device and the polarization-maintaining optical fiber is rotated until the center of the panda eye 246 of the polarization-maintaining optical fiber 245 and the fiber The line connecting the centers of the cores 248 is perpendicular or parallel to the centerline of the installation groove 22 .

Dot curing glue in the installation groove 22 , and use the curing glue to fix the polarization maintaining optical fiber 245 in the installation groove 22 .

Align the first branch 122 and the second branch 124 of the Y-shaped optical waveguide 12 with the two polarization-maintaining fibers 245 of the fiber ring 24 respectively, and clamp them with a clamping device.

S2: providing a broadband light source 4, an optical power meter 5, a coupler 6 and a pigtail assembly 3, the pigtail assembly 3 including a second substrate 30 and a second optical fiber 32 fixed to the second substrate 30;

S3: Make the input end of the coupler 6 electrically communicate with the broadband light source 4 and the optical power meter 5 respectively, weld and fix the output end of the coupler 6 with the second optical fiber 32, and make the other end of the second optical fiber 32 One end is aligned with the incident end 120 of the Y-shaped optical waveguide 12, and aligned with the first input optical fiber 240 and the first branch 122, and aligned with the second input optical fiber 242 and the second branch 124, so that the optical signal of the first branch 122 is coupled to The first input optical fiber 240 couples the optical signal of the second branch 124 to the second input optical fiber 242 .

S4: Make the wide-spectrum light source 4 emit light beams, the light beams emitted by the wide-spectrum light source 4 are filtered by the coupler 6, then transmitted through the pigtail assembly 3, the optical waveguide chip 1 and the optical fiber ring assembly 2, and then transmitted in the optical Interference occurs in the waveguide chip 1, and then reaches the optical power meter 5 through the coupler 6, and the optical power meter 5 detects the power.

Adjust the coupling alignment between the pigtail assembly 3 and the optical fiber ring assembly 2 and the optical waveguide chip 1 respectively, and judge the alignment coupling between the optical waveguide chip 1 and the pigtail assembly 3 and the optical fiber ring assembly 2 according to the power.

In this embodiment, more specifically, two fixtures, two six-dimensional electric stages, a computer, and a motion controller are provided. The computer is used by the user to control the operation process of the direct coupling device, display the camera image and optical power in real time, and monitor the coupling quality online. The motion controller includes a programmable logic controller and a step ladder program, and the motion controller is a device for controlling the actuation of the six-dimensional electric table. The stepping ladder program includes the receiving of computer instructions, instruction understanding, buffer state identification, pulse output and pulse output state monitoring, and confirms whether the end face of the optical waveguide chip is parallel to the end face of the pigtail assembly according to the state of the pulse output.

The X, Y, Z direction translation resolution of the six-dimensional electric stage is 10nm, and the θx, θy, θz direction rotation resolution is 0.002°.

Specifically, two clamps are used to clamp the pigtail assembly 3 and the fiber ring assembly 2 respectively, and the clamps are respectively arranged on the six-dimensional electric table, and the angle adjustment of the six-dimensional electric table is set when adjusting the parallelism and adjusting the optical power. Range, displacement adjustment range and step diameter, adjust the angle between the optical fiber ring assembly 2 and the optical waveguide chip 1 according to the rotation resolution, and gradually adjust the moving range of the six-dimensional electric stage according to the step diameter to adjust the distance between the optical waveguide chip 1 and the optical fiber ring assembly 2 alignment coupling. Preferably, X and Y have a coarse adjustment range in the plane, record the power detected by the optical power meter 5 corresponding to each step value, record the power corresponding to all step values, and adjust the light when the maximum power is detected. The waveguide chip 1 and the fiber ring assembly 2 are fixed.

That is to say, in the present application, after finding the optimal position through rough adjustment, the optimal position is found near the optimal position through fine adjustment. The extraction of the optical power value is acquired by helical inward scanning or parallel scanning.

More specifically, the motion controller sends attitude control signals to the two six-dimensional electric stages; the computer is connected to the optical power meter and the six-dimensional electric stages. In this embodiment, the θz of the six-dimensional electric stage is roughly adjusted with a step of 0.1° to find the best alignment position, and then θz is fine-tuned with a step of 0.05° or 0.01° to determine the optimal alignment position, at this time the output optical power detected by the optical power meter 5 is the maximum. The θx and θy of the six-dimensional electric stage are roughly adjusted with a step of 0.1° to find the best alignment position where the fiber ring component 2 is parallel to the optical waveguide chip 1, and the pigtail component 3 is parallel to the optical waveguide chip 1, and then θx and θy Then fine-tune the determined optimal alignment position with a step of 0.05° or 0.01°. At this time, the contact surfaces of the optical fiber ring assembly 2 and the optical waveguide chip 1, and the contact surfaces of the pigtail assembly 3 and the optical waveguide chip 1 are parallel.

Specifically, the coupling alignment method includes: adjusting the three-dimensional position and three-dimensional angle of the pigtail assembly 3 and the fiber ring assembly 2 through computer control. The motion controller adopts time-division multiplexing technology to divide the 12-axis motors of the two six-dimensional electric tables into two groups, each group controls six dimensions, and uses the two-way pulse interface of the programmable logic controller to control the six dimensions.

Control the rotation of the six-dimensional electric table holding the pigtail assembly 3 and the fiber ring assembly 2, adjust the yaw and pitch of the pigtail assembly 3 and the fiber ring assembly 2, and reduce the polarization angle and the optical waveguide of the pigtail assembly 3 and the fiber ring assembly 2 The angular difference of the polarization angle of the chip. The computer records the output power of the optical power meter, and the position of the maximum power is the fixed position of the optical fiber and the optical waveguide chip.

Preliminary confirmation of the position, by adjusting the X, Y, and Z axes of the six-dimensional electric stage, move the pigtail assembly 3 and the fiber ring assembly 2 to the initial position close to the optical waveguide chip 1, and adjust the θx and θy to move the fiber ring assembly 2. The contact surface in contact with the optical waveguide chip 1 and the contact surface of the pigtail assembly 3 in contact with the optical waveguide chip 1 are adjusted to be parallel.

The range of light coarse adjustment is: the six-dimensional electric platform takes the initial position as the center, makes X, Y within the adjustment range of a rectangular frame with a side length of 100um, that is, within the positive and negative directions of 50um each, and adjusts the tail in turn with a step distance of 1um. Fiber component 3, fiber ring component 2; θz is adjusted at a step of 0.1 degrees to extract the optical power value corresponding to each step, and find the corresponding pigtail component 3 and fiber ring component 2 when the power value is the largest, as a preliminary Confirmed coupling points.

The range of fine-tuning is: the six-dimensional electric table takes the initial position of the maximum power obtained by rough adjustment as the center, and X and Y are within a rectangular frame with a side length of 5um. Every time it moves 0.1um, extract the optical power value once, and find each The optical power corresponding to the step value, and the position corresponding to the maximum optical power is the optimal position.

The optical fiber ring assembly 2 and the pigtail assembly 3 adjust the value of θz at a step distance of 0.01 degrees, and find the corresponding position of the pigtail assembly 3 and optical fiber ring assembly 2 when the power value is the largest, as the final confirmed coupling point.

S5: apply curing glue to the bonding surface of the first branch 122 and the first input optical fiber 240, and apply curing glue to the bonding surface of the second branch 124 and the second input optical fiber 242; and

S6: Curing the curing glue, so that the first branch 122 is connected to the first input optical fiber 240 through the curing glue, and the second branch 124 is connected to the second input optical fiber 242 through the curing glue. The opposite side surfaces of the chip substrate 11 are respectively fixed to the first substrate 20 and the second substrate 30 .

Optionally, in one of the embodiments of the present invention, the angle between the side surface 121 of the Y-shaped optical waveguide 12 and its longitudinal section B is 10°, and the side surface of the optical fiber ring assembly 2 and itself The angle between the longitudinal sections is 15°. An angle difference is formed between the Y-shaped optical waveguide 12 and the pigtail assembly 3 and the optical fiber ring assembly 2, so that the end face of the optical fiber ring assembly 2 and the side surface of the pigtail assembly 3 can be pressed against the opposite sides of the Y-shaped optical waveguide 12 respectively. end face to reduce coupling loss caused by back reflection.

Compared with related technologies, the sensitive ring coupling structure and coupling method provided by this application only need to use an optical power meter and two six-dimensional electric stages to realize the coupling and alignment of the optical waveguide chip 1 and the pigtail assembly 3, The optical waveguide chip 1 only needs to include a Y-branch waveguide, so that there is no need to form straight waveguides on the two sides of the optical waveguide chip 1 opposite to the Y-branch waveguide, so as to use the straight waveguide for decoupling alignment and need to couple 4 port fibers.

In this application, by adjusting the pose of the pigtail assembly 3 and the fiber ring assembly 2, and then according to the optical power value returned by the coupler measured by the optical power meter, the optical waveguide chip 1 and the pigtail assembly 3 and the fiber ring assembly are roughly adjusted and finely adjusted. 2 coupling points. The present invention avoids that the sensitive ring coupling structure has two fusion points inside when it is used in the fiber optic gyroscope, and the optical fiber of the fiber optic ring assembly adopts an array mode, which simplifies the manufacturing process of the fiber optic gyroscope, improves work efficiency, and reduces the cost of fiber fusion. Back reflection and polarization crosstalk improve the measurement accuracy, lifetime and quality of the fiber optic gyroscope.

Finally, the optical parameters of the fabricated sensitive ring coupling structure 100 were tested using the truncation method (i.e. truncation at the two pigtails of the polarization-maintaining fiber ring). 48/52～52/48, polarization crosstalk is better than -30dB; the typical value of insertion loss variation in the full temperature range (-45～70℃) is 0.3dB, and the variation of splitting ratio is better than 2%. The worst value of polarization crosstalk between two polarization maintaining fibers is better than -30dB.

Those skilled in the art can clearly understand that for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units, Completion of modules means that the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above.

Claims (10)

1. A sensitive ring coupling structure is characterized in that, comprises optical waveguide chip, optical fiber ring assembly and pigtail assembly, and described optical waveguide chip comprises chip substrate and the Y-type optical waveguide that is formed on the chip substrate, described The Y-shaped optical waveguide includes a first branch and a second branch, the optical fiber ring assembly includes a first substrate and an optical fiber ring fixed to the first substrate, and the pigtail assembly includes a second substrate and a second substrate. A fixed second optical fiber, the end face of the second optical fiber is aligned with the input end of the Y-shaped optical waveguide and connected by curing glue; the optical fiber ring includes a first input optical fiber and a second input optical fiber, the first branch and the second input optical fiber The first input optical fiber is aligned and connected through curing glue, and the second branch is aligned with the second input optical fiber and connected through curing glue. 2. A sensitive ring coupling structure according to claim 1, characterized in that: the first substrate is provided with two installation grooves, and the optical fiber ring is a ring structure wound by a polarization-maintaining optical fiber, The connecting line between the center of the panda eye and the center of the fiber core of the polarization-maintaining optical fiber is perpendicular or parallel to the center line of the installation groove; the second substrate is provided with an installation groove, and the second optical fiber is a polarization-maintaining optical fiber. Optical fiber, the line connecting the center of the panda eye of the second optical fiber and the center of the fiber core is perpendicular or parallel to the center line of the installation groove; in the three installation grooves, the polarization-maintaining fiber in each installation groove The line connecting the center of the panda eye and the center of its own fiber core is simultaneously perpendicular or parallel to the center line corresponding to the installation slot. 3. a kind of sensitive ring coupling structure according to claim 2, is characterized in that: described sensitive ring coupling structure also comprises broadband light source, optical power meter and coupler; The input end of described coupler is respectively connected with broadband The light source and the optical power meter are connected, the output end of the coupler is connected to one end of the second optical fiber, and the incident end of the Y-shaped optical waveguide is connected to the other end of the second optical fiber. 4 . The sensitive ring coupling structure according to claim 2 , wherein the opposite side surfaces of the chip substrate are respectively fixed to the side surfaces of the first substrate and the side surfaces of the second substrate. 5. A sensitive ring coupling structure according to claim 2, characterized in that: the angle range between the side surface of the Y-shaped optical waveguide and its own longitudinal section is 6-12°, and the side surface of the optical fiber ring assembly The included angle with its own longitudinal section is 10-15°. 6. A coupling method of a sensitive ring coupling structure, characterized in that the coupling method comprises: An optical waveguide chip, an optical fiber ring assembly, and an input-end pigtail assembly are provided. The optical waveguide chip includes a chip substrate and a Y-shaped optical waveguide formed on the chip substrate. The Y-shaped optical waveguide includes a first branch and a second branch. branch, the fiber ring assembly includes a first substrate and a fiber ring fixed to the first substrate; the fiber ring includes a first input fiber and a second input fiber, and the thickness of the first substrate is the same as that of the chip The thickness of the substrate is not the same; aligning the first input fiber with the first branch, and aligning the second input fiber with the second branch; and Applying curing glue to the bonding surface of the first branch and the first input optical fiber, and applying curing glue to the bonding surface of the second branch and the second input optical fiber; and Curing the curing glue, so that the first branch is connected to the first input optical fiber through the curing glue, and the second branch is connected to the second input optical fiber through the curing glue; The pigtail assembly includes a second substrate and a second optical fiber fixed to the second substrate, the thickness of the second substrate is the same as that of the first substrate, and the pigtail assembly is aligned with the input of the Y-shaped optical waveguide end, Apply curing glue to the joint surface of the pigtail assembly and the input end of the Y waveguide, and connect the second optical fiber to the input end of the Y-shaped optical waveguide through curing glue. 7. the coupling method of a kind of sensitive ring coupling structure according to claim 6, is characterized in that: Align the first input fiber and the first branch, align the second input fiber and the second branch, align the input end pigtail assembly and the input end of the Y-shaped waveguide, so that the optical signal of the input end pigtail assembly enters the Y-shaped waveguide At the input end, the optical signal of the first branch is coupled to the first input optical fiber, and the method for coupling the optical signal of the second branch to the second input optical fiber includes: providing a broadband light source, an optical power meter, and a coupler so that the input end of the coupler is electrically connected to the broadband light source and the optical power meter respectively, so that the output end of the coupler is aligned with the second optical fiber; The wide-spectrum light source emits light beams, and the light beams emitted by the wide-spectrum light sources are split by the coupler, then transmitted through the pigtail assembly, the optical waveguide chip and the fiber ring assembly, and generate beam splitting in the optical waveguide chip and combine beams, then reach the optical power meter through the coupler, and detect the power by the optical power meter; and The alignment coupling degree of the first branch and the first input optical fiber and the alignment coupling degree of the second branch and the second input optical fiber are judged according to the power. 8. The coupling method of a sensitive ring coupling structure according to claim 7, characterized in that: the angle between the side surface of the Y-shaped optical waveguide and the direction of its longitudinal section is 6-12°, and the optical fiber ring The angle between the side of the module and its own longitudinal section is 10-15°. 9. the coupling method of a kind of sensitive ring coupling structure according to claim 7, it is characterized in that: when providing broadband light source, optical power meter, coupler, also include providing two clamps and two six-dimensional electric platforms, Utilize two clamps to clamp the pigtail assembly and the fiber ring assembly respectively, and set each clamp on one of the six-dimensional electric tables, and set the angle adjustment range, position adjustment range and step diameter of the six-dimensional electric table , gradually adjust the climbing angle of the six-dimensional electric stage according to the step diameter to adjust the alignment coupling degree of the optical waveguide chip and the fiber ring assembly, and record the power detected by the optical power meter corresponding to each step value, and record all the step values Corresponding power, and fix the optical waveguide chip and fiber ring assembly when the maximum power is detected. 10 . The coupling method of a sensitive ring coupling structure according to claim 9 , wherein the adjustment method of the six-dimensional electric stage includes a rough adjustment step and a fine adjustment step after the rough adjustment. 11 .

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