Double-groove polarization-maintaining coupler and coupling packaging method

Abstract

The invention provides a double-groove polarization-maintaining coupler and a coupling packaging method. The double-groove polarization-maintaining coupler comprises a coupler assembly and a packaging shell assembly used for protecting the coupler assembly. The coupler assembly comprises a lithium niobate optical waveguide chip, an input polarization-maintaining tail fiber coupled to the input side of the lithium niobate optical waveguide chip, and a double-groove output polarization-maintaining tail fiber coupled to the output side of the lithium niobate optical waveguide chip. The double-groove output polarization-maintaining tail fiber comprises two micro-nano V-shaped grooves which are arranged side by side. The coupling packaging method comprises the steps of equipment pretreatment, tail fiber pretreatment, input polarization-maintaining tail fiber treatment, input polarization-maintaining tail fiber preliminary alignment, input polarization-maintaining tail fiber fine alignment, double-groove output polarization-maintaining tail fiber alignment, dispensing curing treatment and packaging. According to the technical scheme, efficient mode field matching is achieved through double-groove coupling, the size of the device can be reduced, meanwhile, the coupling efficiency and the polarization maintaining capacity are remarkably improved, and long-term stable operation of the device in various application environments is ensured through a high-robustness packaging technology.

Description

Technical Field

[0001] This invention belongs to the field of integrated optical device technology, and more specifically, relates to a dual-slot polarization-maintaining coupler and a coupling packaging method. Background Technology

[0002] Lithium niobate (LiNbO3) integrated optical devices have been widely used in high-speed fiber optic communication, high-precision fiber optic sensing (such as fiber optic gyroscopes), and quantum information processing due to their excellent electro-optic, acousto-optic, and nonlinear optical properties. Polarization-maintaining fiber, which maintains the polarization state of optical signals, is a key medium for achieving stable transmission in these systems. The polarization-maintaining coupler, as the core interface device connecting the polarization-maintaining fiber and the lithium niobate waveguide, directly determines the optical path efficiency and stability of the entire system.

[0003] Currently, the mainstream approach for coupling polarization-maintaining fiber to lithium niobate chip waveguides is the three-terminal direct end-face coupling technique. While this technique has a relatively simple structure, it faces significant bottlenecks in practical applications and further miniaturization and performance enhancement. I. Structural Dimensions and Integration: Since the input and output terminals need to be individually aligned and fixed on different ends or sides of the chip, they occupy a large space, which limits the miniaturization and high-density integration of the device.

[0004] II. Performance Consistency: The presence of multiple coupling points leads to an increase in cumulative tolerance, making it difficult to accurately control the consistency of key parameters such as insertion loss (IL) and splitting ratio (D), thus affecting the yield.

[0005] III. Polarization Preservation Performance: Traditional single-point or single-slot coupling structures have limited mode matching capabilities for the optical field, especially in distinguishing between the two orthogonal polarization modes of polarization-preserving light, resulting in high polarization crosstalk and difficulty in improving extinction ratio (PER) performance.

[0006] IV. Long-term reliability: Existing packaging technologies do not adequately protect multiple fragile coupling interfaces. When devices face severe environments such as temperature cycling, mechanical vibration, or humidity changes, their performance is prone to drift or even failure.

[0007] Therefore, for applications such as fiber optic gyroscopes that have stringent requirements for device size, performance consistency, polarization retention capability, and long-term reliability, there is an urgent need for a new coupling structure and coupling packaging solution. Summary of the Invention

[0008] In view of this, the present invention provides a dual-slot bias-maintaining coupler and a coupling packaging method.

[0009] According to a first aspect of the present invention, a dual-slot polarization-maintaining coupler is provided, the dual-slot polarization-maintaining coupler comprising a coupler assembly and a housing assembly for protecting the coupler assembly; The coupler assembly includes a lithium niobate optical waveguide chip, an input polarization-maintaining pigtail coupled to the input side of the lithium niobate optical waveguide chip, and a dual-slot output polarization-maintaining pigtail coupled to the output side of the lithium niobate optical waveguide chip. The dual-groove output polarization-maintaining pigtail includes two micro-nano-level V-grooves arranged side by side.

[0010] Alternatively, the lithium niobate optical waveguide chip is an X-cut Y-propagating lithium niobate chip prepared by focused ion beam etching and proton exchange processes, with a cutting angle of 10°, a length of 12 mm, and a width of 2.8 mm.

[0011] Optionally, the distance between the two V-grooves is 250 μm; the depth of the V-grooves is 60 ± 10 μm, and the angle is 15°.

[0012] Alternatively, the ends of the input polarization-maintaining pigtail and the dual-slot output polarization-maintaining pigtail are bare optical fibers with the coating removed.

[0013] Optionally, the encapsulation housing assembly includes an inner encapsulation sleeve, a middle encapsulation sleeve, and an outer encapsulation sleeve.

[0014] According to a second aspect of the present invention, a coupling and packaging method for any of the above-described dual-slot polarization-maintaining couplers is provided. The coupling and packaging method is implemented based on a coupling system, which includes an SLD depolarization light source, a precision axis-aligned coupling platform, an optical power meter, an extinction ratio tester, an LED point light source curing machine, and a visual system. The coupling encapsulation method includes the following steps: Equipment pretreatment: Turn on the SLD depolarization light source, the optical power meter, the extinction ratio tester, the LED point light source curing machine, and the visual system; Pigtail pretreatment: Prepare the prepared lithium niobate optical waveguide chip, input polarization-maintaining pigtail and dual-slot output polarization-maintaining pigtail, remove the coating layer from the pigtail ends of the input polarization-maintaining pigtail and the dual-slot output polarization-maintaining pigtail and clean them. Input polarization-maintaining pigtail processing: The input polarization-maintaining pigtail is fused to the output jumper of the SLD depolarizing light source. The optical power and extinction ratio of the end face of the input polarization-maintaining pigtail are tested using the optical power meter and the extinction ratio tester, and the optical power is recorded as P0 and the extinction ratio as PER0. Initial alignment of the input polarization-maintaining pigtail: Align the end face of the input polarization-maintaining pigtail with the input of the lithium niobate optical waveguide chip under the visual system; Input polarization-maintaining pigtail precision alignment: The alignment accuracy is adjusted by the precision axis coupling platform. Under the monitoring of the optical power meter, the angle of the input polarization-maintaining pigtail is adjusted so that its stress axis is completely aligned with the polarization principal axis of the lithium niobate optical waveguide chip. Dual-slot output polarization-maintaining pigtail alignment: Insert the end face of the dual-slot output polarization-maintaining pigtail into the adapter and into the channel of the optical power meter. Record the optical power values ​​P1 and P2 when the stress axis of the dual-slot output polarization-maintaining pigtail is completely aligned with the polarization principal axis of the lithium niobate optical waveguide chip. Then insert the dual-slot output polarization-maintaining pigtail into the channel of the extinction ratio tester and record the extinction ratio values ​​PER1 and PER2. Dispensing and curing process: The coupling points of the lithium niobate optical waveguide chip and the input polarization-maintaining pigtail, as well as the coupling points of the lithium niobate optical waveguide chip and the dual-slot output polarization-maintaining pigtail, are fixed by dispensing adhesive, and the UV adhesive at each coupling point is cured using the LED point light source curing machine. Encapsulation: The coupler assembly is encapsulated using an encapsulation housing assembly.

[0015] Optionally, in the step of processing the input polarization-maintaining pigtail, the SLD depolarizing light source adopts a working wavelength of 1310nm and 1550nm. And / or, In the step of input polarization-maintaining fiber processing, the measurement range of the optical power meter is -70 dBm to +10 dBm.

[0016] Optionally, in the step of processing the input polarization-maintaining pigtail, the input optical power range of the extinction ratio tester is -40dBm to +10dBm. And / or, In the dispensing and curing process, the LED point light source curing machine operates at a wavelength of 365nm.

[0017] Alternatively, the precise axis coupling platform is a six-dimensional displacement platform with displacement directions of X, Y, Z and θX, θY, θZ.

[0018] Optionally, the optical power meter automatically calculates the insertion loss and splitting ratio based on the recorded optical powers P0, P1, and P2, and according to the following formula; The expression for insertion loss is: The expression for the spectrophotometer ratio is: Where IL is the insertion loss, D is the splitting ratio, P0 is the optical power of the input polarization-maintaining pigtail, and P1 and P2 are the optical power of the output polarization-maintaining pigtail, respectively.

[0019] The beneficial effects of this invention are as follows: The dual-slot polarization-maintaining coupler of this invention achieves efficient mode-field matching through dual-slot coupling. This solution can significantly improve coupling efficiency and polarization maintenance capability while reducing device size, and ensures long-term stable operation of the device in various application environments through a highly robust packaging process.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] The present invention can be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which the same or similar reference numerals are used throughout the drawings to denote the same or similar parts.

[0022] Figure 1 A schematic diagram of a dual-slot polarization-maintaining coupler according to an embodiment of the present invention is shown; Figure 2 A flowchart illustrating the implementation of a coupling packaging method for a dual-slot polarization-maintaining coupler according to an embodiment of the present invention is shown. Figure 3 A connection diagram of a coupling system according to an embodiment of the present invention is shown; Figure 4 A schematic diagram of test data for a dual-slot polarization-maintaining coupler according to an embodiment of the present invention is shown. Detailed Implementation

[0023] To enable those skilled in the art to more fully understand the technical solutions of the present invention, exemplary embodiments of the present invention will be described more comprehensively and in detail below with reference to the accompanying drawings. Obviously, the one or more embodiments of the present invention described below are merely one or more specific ways to implement the technical solutions of the present invention, and are not exhaustive. It should be understood that other ways belonging to a general inventive concept can be used to implement the technical solutions of the present invention, and should not be limited to the embodiments described exemplary. Based on one or more embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] Example: Figure 1 A schematic diagram of a dual-slot polarization-maintaining coupler according to an embodiment of the present invention is shown. (Refer to...) Figure 1 The dual-slot polarization-maintaining coupler of this invention includes a coupler assembly and a housing assembly for protecting the coupler assembly. The coupler assembly includes a lithium niobate optical waveguide chip 101, an input polarization-maintaining pigtail 102 coupled to the input side of the lithium niobate optical waveguide chip 101, and a dual-slot output polarization-maintaining pigtail 103 coupled to the output side of the lithium niobate optical waveguide chip 101. The dual-slot output polarization-maintaining pigtail 103 includes two micro-nano-level V-slots arranged side by side; The input polarization-maintaining pigtail 102 is used to couple the incident optical signal to the lithium niobate optical waveguide chip 101; The dual-slot output polarization-maintaining pigtail 103 is used to couple and output the optical signal processed by the lithium niobate optical waveguide chip 101.

[0025] Furthermore, in this embodiment of the invention, the lithium niobate optical waveguide chip 101 is an X-cut Y-propagating lithium niobate chip prepared by focused ion beam etching and proton exchange processes, with a cutting angle of 10°, a length of 12 mm, and a width of 2.8 mm.

[0026] Furthermore, in this embodiment of the invention, the spacing between the two V-grooves of the dual-groove output polarization-maintaining pigtail 103 is 250 μm; the depth of the V-groove is 60 ± 10 μm, and the angle is 15°.

[0027] Furthermore, in this embodiment of the invention, the ends of the input polarization-maintaining pigtail 102 and the dual-slot output polarization-maintaining pigtail 103 are bare optical fibers with the coating removed.

[0028] Furthermore, in this embodiment of the invention, the encapsulation housing assembly includes an inner encapsulation sleeve 104, a middle encapsulation sleeve 105, and an outer encapsulation sleeve 106.

[0029] Specifically, in this embodiment of the invention, the inner encapsulation sleeve 104 is implemented using a short steel tube with a diameter of φ1.9*0.1*3mm, the middle encapsulation sleeve 105 is implemented using a quartz tube with a diameter of φ2.5*2.0*20mm, and the outer encapsulation sleeve 106 is implemented using a stainless steel tube with a diameter of φ3.0*0.2*25mm.

[0030] Accordingly, based on the dual-slot bias-maintaining coupler of the present invention, the present invention also proposes a coupling and packaging method for the dual-slot bias-maintaining coupler.

[0031] Figure 2 The flowchart illustrates the implementation of the coupling and packaging method for a dual-slot polarity-maintaining coupler according to an embodiment of the present invention. Figure 3 A connection diagram of the coupling system according to an embodiment of the present invention is shown. (Refer to...) Figure 2 and Figure 3 The coupling and encapsulation method of this invention is based on a coupling system, which includes an SLD depolarization light source, a precision axis coupling platform, an optical power meter, an extinction ratio tester, an LED point light source curing machine, and a visual system. The coupling encapsulation method includes the following steps: S1 equipment pretreatment: Turn on the SLD depolarization light source, optical power meter, extinction ratio tester, LED point light source curing machine and visual system, and adjust parameters such as light source output power; S2 pigtail pretreatment: Prepare the prepared lithium niobate optical waveguide chip, input polarization-maintaining pigtail and dual-slot output polarization-maintaining pigtail, remove the coating layer from the pigtail ends of the input polarization-maintaining pigtail and dual-slot output polarization-maintaining pigtail and clean them. S3 Input Polarization Maintaining Fiber Processing: The input polarization maintaining fiber is fused to the output jumper of the SLD depolarizing light source. The optical power and extinction ratio of the end face of the input polarization maintaining fiber are tested using an optical power meter and an extinction ratio tester, and the optical power is recorded as P0 and the extinction ratio as PER0. S4 Input Polarization Maintaining Fiber Initial Alignment: Align the end face of the input polarization maintaining fiber with the input of the lithium niobate optical waveguide chip under a visual system. S5 Input Polarization Maintaining Pigtail Precision Alignment: By precisely adjusting the alignment accuracy through the axis coupling platform, and under the monitoring of the optical power meter, the angle of the input polarization maintaining pigtail is adjusted to ensure that its stress axis is completely aligned with the polarization principal axis of the lithium niobate optical waveguide chip. S6 Dual-Slot Output Polarization Maintaining Pigtail Alignment: Insert the end face of the dual-slot output polarization maintaining pigtail into the adapter and into the channel of the optical power meter. Record the optical power values ​​P1 and P2 when the stress axis of the dual-slot output polarization maintaining pigtail is completely aligned with the polarization principal axis of the lithium niobate optical waveguide chip. Then insert the dual-slot output polarization maintaining pigtail into the channel of the extinction ratio tester and record the extinction ratio values ​​PER1 and PER2. S7 dispensing and curing process: The coupling points of the lithium niobate optical waveguide chip and the input polarization-maintaining pigtail, as well as the coupling points of the lithium niobate optical waveguide chip and the dual-slot output polarization-maintaining pigtail, are fixed by dispensing adhesive, and the UV adhesive at each coupling point is cured using an LED point light source curing machine. S8 package: The coupler component is encapsulated using a package housing assembly.

[0032] Specifically, in the embodiment of the present invention, in the S7 dispensing and curing process, a UV adhesive with low shrinkage and high light transmittance is used to cure the coupling point, and the shrinkage of the UV adhesive is less than 1%.

[0033] Furthermore, in this embodiment of the invention, in the step of input polarization-maintaining fiber processing in S3, the SLD depolarization light source uses a working wavelength of 1310nm and 1550nm. And / or, During the S3 input polarization-maintaining fiber processing step, the optical power meter has a measurement range of -70 dBm to +10 dBm.

[0034] Furthermore, in this embodiment of the invention, in the step of input polarization-maintaining fiber processing in S3, the input optical power range of the extinction ratio tester is -40dBm ~ +10dBm; And / or, In the S7 dispensing and curing process, the LED point light source curing machine operates at a wavelength of 365nm.

[0035] Furthermore, in this embodiment of the invention, the precise axis-coupled platform is a six-dimensional displacement platform, with displacement directions including the X, Y, Z, and θ directions. X θ Y θ Z direction.

[0036] Furthermore, in this embodiment of the invention, the optical power meter automatically calculates the insertion loss and splitting ratio based on the recorded optical powers P0, P1, and P2, and according to the following formula; The expression for insertion loss is: The expression for the spectrophotometer ratio is: Where IL is the insertion loss, D is the splitting ratio, P0 is the optical power of the input polarization-maintaining pigtail, and P1 and P2 are the optical power of the output polarization-maintaining pigtail, respectively.

[0037] Figure 4 A schematic diagram of test data for a dual-slot polarization-maintaining coupler according to an embodiment of the present invention is shown. Tests revealed that the dual-slot polarization-maintaining coupler fabricated using the coupling and packaging method of this embodiment exhibits an insertion loss of 2.1 dB and a polarization extinction ratio of ≥35 dB at wavelengths of 1550 nm and 1310 nm. After temperature cycling tests, the performance change is less than 0.3 dB, the splitting ratio change is <1%, and the full-temperature polarization extinction ratio is >30 dB, demonstrating excellent stability.

[0038] Specifically, the coupling and packaging method of the dual-slot polarization-maintaining coupler according to an embodiment of the present invention will be described in more detail below: The lithium niobate optical waveguide chip was placed on a precision alignment coupling platform. The pigtail end of the input polarization-maintaining fiber was fused to the output end of the SLD depolarizing light source using a jumper. The optical power of the input polarization-maintaining fiber was measured using an optical power meter, and the P0 value was recorded. The extinction ratio of the input polarization-maintaining fiber was measured using an extinction ratio tester, and the PER0 value was recorded. Under the visual system, the X, Y, Z, θX, θY, and θZ directions were adjusted by adjusting the precision alignment coupling platform, thereby adjusting the angle of the input polarization-maintaining fiber to ensure that its stress axis is completely aligned with the polarization principal axis of the lithium niobate optical waveguide chip.

[0039] Connect the two polarization-maintaining pigtails of the dual-slot output polarization-maintaining pigtail to the optical power meter. Under the visual system, adjust the X, Y, Z, θX, θY, and θZ directions by adjusting the precision axis coupling platform, thereby adjusting the angle of the dual-slot output polarization-maintaining pigtail to ensure that its output stress axis is perfectly aligned with the polarization principal axis of the lithium niobate optical waveguide chip. Test and record the optical power P1 and P2 using the optical power meter. Then, insert the two polarization-maintaining pigtails of the dual-slot output polarization-maintaining pigtail into an extinction ratio tester and record the extinction ratios PER1 and PER2. Apply UV glue to the coupling point and cure it using an LED point light source curing machine. After curing, the optical power meter will calculate the insertion loss and splitting ratio using formulas based on the recorded optical power P0, P1, and P2.

[0040] After curing, the coupler assembly is inserted into the inner encapsulation sleeve, and low-temperature silicone rubber is applied and cured at room temperature to center the lithium niobate waveguide chip in the inner encapsulation sleeve. Then, the middle encapsulation sleeve is placed on the inner encapsulated coupler assembly, maintaining symmetry on both sides. Next, AB two-component low-stress adhesive is used for potting to fully protect the coupling point and the lithium niobate waveguide chip. Finally, the outer encapsulation sleeve is placed to protect the internal coupler assembly from strong external impacts.

[0041] Existing methods for coupling polarization-maintaining fibers to lithium niobate chips often employ direct end-face coupling, which suffers from low coupling efficiency and poor long-term reliability. This invention addresses this issue by employing a dual-slot coupling structure to improve mode field matching and optimizing packaging processes to ensure long-term reliability, providing an effective solution for high-performance integrated optical devices. The dual-slot polarization-maintaining coupler of this invention expands the mode field overlap region through the dual-slot coupling structure, effectively improving coupling efficiency and polarization-maintaining characteristics. The optimized packaging process ensures the stability of the coupling point under various environmental conditions.

[0042] The dual-slot polarization-maintaining coupler of this invention employs a dual-slot output polarization-maintaining fiber-optic coupling structure, effectively improving mode field matching and offering advantages such as high coupling efficiency, good polarization retention performance, and small package size. The coupling and packaging method of this invention achieves precise alignment of the polarization-maintaining axis through optical power monitoring and automatically calculates insertion loss and beam splitting ratio using formulas, facilitating device performance assessment. The dual-slot polarization-maintaining coupler and coupling and packaging method of this invention ensure long-term device reliability through optimized curing processes and hermetic encapsulation. Compared to traditional coupling methods, it not only offers superior performance but also boasts good process repeatability, making it suitable for mass production.

[0043] While one or more embodiments of the present invention have been described above, those skilled in the art will recognize that the present invention can be implemented in any other form without departing from its spirit and scope. Therefore, the embodiments described above are illustrative and not restrictive, and many modifications and substitutions will be apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A dual-slot polarization-maintaining coupler, characterized in that, Includes a coupler assembly and a housing assembly for protecting the coupler assembly; The coupler assembly includes a lithium niobate optical waveguide chip, an input polarization-maintaining pigtail coupled to the input side of the lithium niobate optical waveguide chip, and a dual-slot output polarization-maintaining pigtail coupled to the output side of the lithium niobate optical waveguide chip. The dual-groove output polarization-maintaining pigtail includes two micro-nano-level V-grooves arranged side by side.

2. The dual-slot polarity-maintaining coupler according to claim 1, characterized in that, The lithium niobate optical waveguide chip is an X-cut Y-propagating lithium niobate chip prepared by focused ion beam etching and proton exchange processes. The cutting angle is 10°, the length is 12mm, and the width is 2.8mm.

3. The dual-slot polarity-maintaining coupler according to claim 1, characterized in that, The distance between the two V-grooves is 250 μm; the depth of the V-grooves is 60 ± 10 μm, and the angle is 15°.

4. The dual-slot polarity-maintaining coupler according to claim 1, characterized in that, The ends of the input polarization-maintaining pigtail and the dual-slot output polarization-maintaining pigtail are bare optical fibers with the coating stripped off.

5. The dual-slot polarity-maintaining coupler according to claim 1, characterized in that, The encapsulation housing assembly includes an inner encapsulation sleeve, a middle encapsulation sleeve, and an outer encapsulation sleeve.

6. The coupling and packaging method of the dual-slot polarity-maintaining coupler according to any one of claims 1-5, characterized in that, The coupling and encapsulation method is based on a coupling system, which includes an SLD depolarizing light source, a precision axis-aligned coupling platform, an optical power meter, an extinction ratio tester, an LED point light source curing machine, and a visual system. The coupling encapsulation method includes the following steps: Equipment pretreatment: Turn on the SLD depolarization light source, the optical power meter, the extinction ratio tester, the LED point light source curing machine, and the visual system; Pigtail pretreatment: Prepare the prepared lithium niobate optical waveguide chip, input polarization-maintaining pigtail and dual-slot output polarization-maintaining pigtail, remove the coating layer from the pigtail ends of the input polarization-maintaining pigtail and the dual-slot output polarization-maintaining pigtail and clean them. Input polarization-maintaining pigtail processing: The input polarization-maintaining pigtail is fused to the output jumper of the SLD depolarizing light source. The optical power and extinction ratio of the end face of the input polarization-maintaining pigtail are tested using the optical power meter and the extinction ratio tester, and the optical power is recorded as P0 and the extinction ratio as PER0. Initial alignment of the input polarization-maintaining pigtail: Align the end face of the input polarization-maintaining pigtail with the input of the lithium niobate optical waveguide chip under the visual system; Input polarization-maintaining pigtail precision alignment: The alignment accuracy is adjusted by the precision axis coupling platform. Under the monitoring of the optical power meter, the angle of the input polarization-maintaining pigtail is adjusted so that its stress axis is completely aligned with the polarization principal axis of the lithium niobate optical waveguide chip. Dual-slot output polarization-maintaining pigtail alignment: Insert the end face of the dual-slot output polarization-maintaining pigtail into the adapter and into the channel of the optical power meter. Record the optical power values ​​P1 and P2 when the stress axis of the dual-slot output polarization-maintaining pigtail is completely aligned with the polarization principal axis of the lithium niobate optical waveguide chip. Then insert the dual-slot output polarization-maintaining pigtail into the channel of the extinction ratio tester and record the extinction ratio values ​​PER1 and PER2. Dispensing and curing process: The coupling points of the lithium niobate optical waveguide chip and the input polarization-maintaining pigtail, as well as the coupling points of the lithium niobate optical waveguide chip and the dual-slot output polarization-maintaining pigtail, are fixed by dispensing adhesive, and the UV adhesive at each coupling point is cured using the LED point light source curing machine. Encapsulation: The coupler assembly is encapsulated using an encapsulation housing assembly.

7. The coupling and packaging method of the dual-slot polarity-maintaining coupler according to claim 6, characterized in that, In the step of processing the input polarization-maintaining pigtail, the SLD depolarizing light source uses operating wavelengths of 1310nm and 1550nm. And / or, In the step of input polarization-maintaining fiber processing, the measurement range of the optical power meter is -70 dBm to +10 dBm.

8. The coupling and packaging method of the dual-slot polarity-maintaining coupler according to claim 6, characterized in that, In the step of input polarization-maintaining fiber processing, the input optical power range of the extinction ratio tester is -40dBm to +10dBm; And / or, In the dispensing and curing process, the LED point light source curing machine operates at a wavelength of 365nm.

9. The coupling and packaging method of the dual-slot polarity-maintaining coupler according to claim 6, characterized in that, The precise axis-coupled platform is a six-dimensional displacement platform, with displacement directions in the X, Y, Z, and θ directions. X θ Y θ Z direction.

10. The coupling and packaging method of the dual-slot polarity-maintaining coupler according to claim 6, characterized in that, The optical power meter automatically calculates the insertion loss and splitting ratio based on the recorded optical powers P0, P1, and P2, and according to the following formula. The expression for insertion loss is: The expression for the spectrophotometer ratio is: Where IL is the insertion loss, D is the splitting ratio, P0 is the optical power of the input polarization-maintaining pigtail, and P1 and P2 are the optical power of the output polarization-maintaining pigtail, respectively.

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