Polarization maintaining fiber connector and method of making same

Abstract

This invention proposes a polarization-maintaining fiber optic connector and its manufacturing method, belonging to the technical field of fiber optic connectors, to solve the technical problem of easy misalignment during the process of moving the "panda eye" alignment to a heating furnace for curing. The polarization-maintaining fiber optic connector of this invention includes a ferrule and a polarization-maintaining fiber inserted into the ferrule, with a tail sleeve at the end of the ferrule. The manufacturing method includes: filling the ferrule with thermosetting adhesive; inserting the polarization-maintaining fiber into the ferrule; fixing the ferrule with a clamp and moving it under an optical microscope to align the "panda eye" in the polarization-maintaining fiber; using a moving heat source to heat the polarization-maintaining fiber optic connector in situ to pre-cure the thermosetting adhesive; removing the ferrule from the clamp and transferring it to a heating furnace for complete curing. This invention directly controls the polarization-maintaining angle and extinction ratio of the "panda eye" from the structure and manufacturing method of the polarization-maintaining connector. The manufacturing process of this polarization-maintaining connector is simple and easy to implement, with stable quality and optimal extinction ratio.

Description

Technical Field

[0001] This invention belongs to the technical field of fiber optic connectors, and particularly relates to a polarization-maintaining fiber optic connector and its manufacturing method. Background Technology

[0002] With increasingly stringent requirements for polarization state control in coherent optical communication and fiber optic gyroscopes, polarization-maintaining fibers are becoming increasingly necessary. Compared to traditional fiber optic patch cords, polarization-maintaining fibers offer advantages such as ensuring the direction of linear polarization remains unchanged, improving the coherent signal-to-noise ratio, and enabling high-precision measurement of physical quantities. Polarization-maintaining fibers are generally classified into geometric polarization-maintaining fibers and stress-type polarization-maintaining fibers. Geometric polarization-maintaining fibers primarily have an elliptical core and are used in specialized applications. Stress-type polarization-maintaining fibers include panda-shaped, elliptical, butterfly-shaped, and bowtie-shaped fibers.

[0003] Panda-type polarization-maintaining fiber possesses inherent advantages in birefringence, geometric properties, structural symmetry, and longitudinal uniformity. Furthermore, its simple manufacturing process makes it suitable for mass production, hence its widespread use in China. The structure of panda-type polarization-maintaining fiber is as follows: Figure 1 As shown, this includes the fiber core and stress bars (panda eyes) on both sides. The stress bars generate stress in the fiber, which is beneficial for light to propagate with polarization in only one direction. When the polarization-maintaining fiber is terminated through a fiber optic connector, the stress bars should be aligned with the connector's alignment key. Whether the alignment with the alignment key is correct directly determines the transmission function of the polarization-maintaining fiber connector link; generally, an angular deviation of <±5° is required, thereby indirectly ensuring the extinction ratio.

[0004] To align the panda eye connector with the connector mating key, the conventional production method is to fill the connector core with thermosetting adhesive. Before the adhesive has cured, the core is rotated and aligned with the panda eye under a magnifying glass. After alignment, the core is placed in a curing oven for curing. The problem with this method is that after aligning the panda eye, the still-uncured connector core needs to be moved from the fixture to the oven for heating and curing. During this process, the core is prone to rotation under stress, causing the aligned core to rotate. If the panda eye's offset angle is too large (>5°), the connector must be cut and a new connector head added, wasting time and resulting in inconsistent quality.

[0005] To prevent rotation after the polarization angle is aligned (like a panda eye), the structure of the polarization-maintaining connector is usually improved. For example, patent publication number CN216118092U discloses a polarization-maintaining connector. This connector includes a frame, a ferrule, an angle fixing ring, and a stop. The ferrule is disposed within the frame. The angle fixing ring is slidably connected to the ferrule along the axial direction, and rotation of the angle fixing ring can drive the ferrule to rotate. The outer periphery of the stop is fixedly connected to the frame, and the angle fixing ring passes through the stop. The inner wall of the stop has a filling groove that extends from the end of the stop away from the ferrule towards the end closer to the ferrule. The outer periphery of the angle fixing ring has an anti-rotation groove, and the filling groove and the anti-rotation groove at least partially overlap along the axial direction of the frame. By injecting glue into the filling groove, the glue solidifies and forms a fixed structure between the angle fixing ring and the stop. The polarization-maintaining connector provided by this invention prevents the angle fixing ring from rotating after the polarization angle is adjusted, thus improving the stability of the polarization-maintaining connector. However, this polarization-maintaining connector is significantly more expensive than traditional connectors, making it difficult to meet practical applications. Furthermore, patent publication number CN116184576A discloses a high extinction ratio polarization-maintaining fiber connector and its manufacturing method. The manufacturing method includes: inserting the core of the polarization-maintaining fiber into the core through-hole of the ferrule; injecting 353ND adhesive into the core through-hole to adjust the cat's-eye direction of the polarization-maintaining fiber; applying UV adhesive to the outlet of the core through-hole and irradiating with a UV lamp to pre-fix the core; allowing the pre-fixed ferrule to stand at a first preset temperature for a first preset time; and subjecting the ferrule after standing for the first preset time to gradient heating and baking to fix the core and ferrule. This patent primarily improves the extinction ratio by reducing the stress caused by adhesive curing on the optical fiber; and by applying UV adhesive at the core through-hole to pre-fix the polarization-maintaining fiber, preventing free rotation. However, because the amount of UV adhesive applied at the fiber core through-hole is small and located at the head, after the "panda eye" (referring to the small area around the connector's head), the stress will be transmitted to the curing end of the fiber core during the process of the connector moving from the fixture to the heating oven, making it difficult to achieve a good pre-fixation effect. Summary of the Invention

[0006] To address the technical problem of misalignment during the curing process in a heating furnace after the panda eye fiber optic connector is aligned, this invention proposes a polarization-maintaining fiber optic connector and its manufacturing method. This method directly controls the polarization-maintaining angle and extinction ratio of the panda eye fiber optic connector through its structure and manufacturing process. The manufacturing process of this polarization-maintaining connector is simple and easy to implement, resulting in stable quality and optimal extinction ratio.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ferrule and a polarization-maintaining fiber inserted into the ferrule, the ferrule having a tail sleeve at its tail end; the manufacturing method comprising:

[0009] (1) Fill the ferrule and tail sleeve with thermosetting adhesive, and insert the polarization-maintaining fiber into the ferrule from the tail sleeve end.

[0010] (2) Fix the ferrule with a flange clamp and move it to the optical microscopy system to position the panda eye direction in the polarization-maintaining fiber;

[0011] (3) Use a heat source to heat the polarization-maintaining fiber optic connector in situ to pre-cure the thermosetting adhesive;

[0012] (4) Remove the insert from the flange clamp and let it cure completely in the heating furnace.

[0013] The insert is a ceramic insert.

[0014] The tail sleeve is a metal tail sleeve. The tail sleeve protects the polarization-maintaining fiber and reduces the risk of breakage when the fiber is bent. Furthermore, the metal tail sleeve has good thermal conductivity, resulting in a better pre-curing effect.

[0015] The thermosetting adhesive is an epoxy resin adhesive, polyurethane adhesive, amino resin adhesive, phenolic resin adhesive, or acrylic resin adhesive.

[0016] The heat source is either a wind-heated or solar-heated heat source.

[0017] The optical microscopy system is a CCD camera.

[0018] The specific method of in-situ heating in step (3) is as follows: after positioning is completed, the polarization-maintaining fiber and ferrule are not moved, and a heat source is used to heat the polarization-maintaining fiber connector.

[0019] When heating the polarization-maintaining fiber optic connector, the heating temperature of the heat source is 100-200℃, and the heating time is 1-6 minutes.

[0020] The curing temperature in the heating furnace is 80-200℃, and the time is 8-60 minutes.

[0021] The beneficial effects of this invention are as follows: After the panda eye alignment is completed, this invention performs in-situ curing on the polarization-maintaining fiber connector, allowing the thermosetting adhesive on the ferrule or tail sleeve to pre-cure, thus preventing stress from being transferred to the fiber core head during the movement of the polarization-maintaining fiber. This effectively solves the problem of fiber core movement and rotation during the connector's movement from the fixture to the heating furnace after panda eye alignment, making it convenient, efficient, and significantly improving yield. Actual production verification shows that polarization-maintaining connectors made using this invention can have the panda eye offset angle controlled within ±1°, an extinction ratio exceeding 25dB, and a yield exceeding 97%. Furthermore, the equipment cost required for this invention is low, the method is simple and easy to master, the quality is stable and reliable, and the economic benefits are significant. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a polarization-maintaining fiber.

[0024] Figure 2 This is a schematic diagram illustrating the fabrication of the polarization-maintaining fiber optic connector of the present invention.

[0025] In the diagram, 1 is the insert; 2 is the tail sleeve; 3 is the thermosetting adhesive; and 4 is the heat source. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] A method for manufacturing a polarization-maintaining fiber optic connector, such as Figure 2 As shown, the polarization-maintaining fiber connector includes a ferrule 1 and a polarization-maintaining fiber inserted into the ferrule 1. The ferrule 1 has a tail sleeve 2 at its tail end; the tail sleeve 2 is fixedly connected to the ferrule 1, serving to protect the polarization-maintaining fiber and reducing the risk of breakage when the fiber is bent. The manufacturing method includes:

[0028] (1) Fill the ferrule 1 and tail sleeve 2 with thermosetting adhesive 3, and insert the polarization maintaining fiber into the ferrule 1 from the tail sleeve 2 end.

[0029] (2) Fix the ferrule 1 with a flange clamp and move it to the optical microscopy system to position the panda eye direction in the polarization-maintaining fiber;

[0030] (3) Heat source 4 is used to heat the polarization-maintaining fiber optic connector in situ to pre-cure the thermosetting adhesive 3.

[0031] (4) Remove the insert 1 from the flange clamp and let it cure completely in the heating furnace.

[0032] The ferrule 1 is a ceramic ferrule 1. A chamfer can be provided on the outer periphery of the front end of the ceramic ferrule 1 to facilitate mating between the ceramic ferrule 1 and the mating assembly; the fiber optic jack at the rear end of the ceramic ferrule 1 is flared to facilitate the smooth insertion of the polarization-maintaining fiber into the fiber optic jack. The minimum diameter of the fiber optic jack is set to be slightly larger than the diameter of the polarization-maintaining fiber to facilitate the smooth insertion of the polarization fiber and to allow for the filling of thermosetting adhesive 3.

[0033] The tail sleeve 2 is a metal tail sleeve 2, and a large cavity is provided between the tail sleeve 2 and the insert 1 for filling with thermosetting adhesive 3. The metal tail sleeve 2 has good thermal conductivity and can produce a good pre-curing effect when heated.

[0034] The thermosetting adhesive 3 is an epoxy resin adhesive, but other types of thermosetting adhesive 3 can also be used, as long as they meet the usage requirements.

[0035] The heat source 4 refers to a tool that is easy to access and quick to heat, making it easier to meet the requirements of rapid on-site processing. Furthermore, the heat source 4 is a wind-heating type or a photothermal type heat source. The wind-heating type uses hot air for heating, such as a hot air blower; the photothermal type heat source uses a light source that is excited by thermal energy, such as a heating lamp.

[0036] The optical microscopy system is a CCD camera.

[0037] The specific method of in-situ heating in step (3) is as follows: after positioning is completed, the polarization-maintaining fiber and ferrule 1 are not moved, and the polarization-maintaining fiber connector is heated by heat source 4.

[0038] When heating the polarization-maintaining fiber optic connector, the heating temperature of heat source 4 is 100-200℃, and the heating time is 1-6 minutes.

[0039] The curing temperature in the heating furnace is 80-200℃, and the time is 8-60 minutes.

[0040] Example 1

[0041] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0042] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0043] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0044] (3) Use a 150°C hot air gun to heat the metal tail sleeve at the end of the ceramic ferrule for 3 minutes until the epoxy resin adhesive is pre-cured.

[0045] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 120℃ and the time is 20min.

[0046] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0047] The final polarization-maintaining fiber optic connector was tested, and the offset angle of the panda eye could be controlled within ±1°, and the extinction ratio could reach more than 25dB.

[0048] Example 2

[0049] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0050] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0051] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0052] (3) Use a 180°C hot air gun to heat the metal tail sleeve at the end of the ceramic ferrule for 3 minutes until the epoxy resin adhesive is pre-cured.

[0053] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 125℃ and the time is 25min.

[0054] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0055] Example 3

[0056] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0057] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0058] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0059] (3) Use a 100°C hot air gun to heat the metal tail sleeve at the end of the ceramic insert for 6 minutes until the epoxy resin glue is pre-cured.

[0060] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 120℃ and the time is 20min.

[0061] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0062] Example 4

[0063] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0064] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0065] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0066] (3) Use a 200°C hot air gun to heat the metal tail sleeve at the end of the ceramic insert for 1 minute until the epoxy resin adhesive is pre-cured.

[0067] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 120℃ and the time is 20min.

[0068] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0069] Example 5

[0070] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0071] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0072] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0073] (3) Use a 150°C hot air gun to heat the metal tail sleeve at the end of the ceramic ferrule for 4 minutes until the epoxy resin adhesive is pre-cured.

[0074] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 120℃ and the time is 20min.

[0075] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0076] Example 6

[0077] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0078] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0079] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0080] (3) Use a 160°C hot air gun to heat the metal tail sleeve at the end of the ceramic ferrule for 2.5 minutes until the epoxy resin adhesive is pre-cured.

[0081] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 110℃ and the time is 25min.

[0082] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0083] Example 7

[0084] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0085] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0086] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0087] (3) Use a 150°C hot air gun to heat the metal tail sleeve at the end of the ceramic ferrule for 3 minutes until the epoxy resin adhesive is pre-cured.

[0088] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 80℃ and the time is 60min.

[0089] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0090] Example 8

[0091] A method for manufacturing a polarization-maintaining fiber optic connector, the connector comprising a ceramic ferrule and a polarization-maintaining fiber inserted within the ceramic ferrule, wherein the ferrule has a metal tail sleeve at its tail; the manufacturing method includes:

[0092] (1) Fill the ceramic ferrule with epoxy resin glue, and insert the polarization-maintaining fiber from the metal tail sleeve into the fiber optic jack of the ceramic ferrule.

[0093] (2) Fix the ceramic ferrule with a flange clamp and move it to the CCD camera to position the panda eye direction in the polarization-maintaining fiber.

[0094] (3) Use a 150°C hot air gun to heat the metal tail sleeve at the end of the ceramic ferrule for 3 minutes until the epoxy resin adhesive is pre-cured.

[0095] (4) Remove the insert from the flange clamp and let it be completely cured in the heating furnace. The curing temperature in the furnace is 200℃ and the time is 8min.

[0096] (5) Add components to the fully cured polarization-maintaining fiber optic connector, polish the end face, and inspect the end face.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of manufacturing a polarization maintaining fiber connector, the polarization maintaining fiber connector comprising a ferrule and a polarization maintaining fiber inserted into the ferrule, a tail portion of the ferrule being provided with a tail sleeve; characterized in that, The manufacturing method comprises: (1) filling the hot-setting glue in the ferrule and the tail sleeve, and inserting the polarization maintaining optical fiber into the ferrule from the tail sleeve end; (2) fixing the ferrule by using a clamp and moving to the optical microscopic system to align the panda eye in the polarization maintaining optical fiber; (3) in-situ heating the polarization maintaining optical fiber connector by using a heat source to make the hot-setting glue pre-solidify, wherein the temperature of the heat source is 100-200℃ and the time is 1-6min during the in-situ heating; (4) taking out the ferrule from the clamp and moving to the heating furnace to completely solidify.

2. The method of making a polarization maintaining fiber connector according to claim 1, wherein, The ferrule is a ceramic ferrule.

3. The method of making a polarization maintaining fiber connector according to claim 2, wherein, The tail sleeve is a metal tail sleeve.

4. The method of making a polarization maintaining fiber connector according to claim 3, wherein, The hot-setting glue is epoxy resin glue, polyurethane glue, amino resin glue, phenolic resin glue or acrylic resin glue.

5. The method of making a polarization maintaining fiber connector according to claim 4, wherein, The heat source is a wind heat type or a light heat type heat source.

6. The method of making a polarization maintaining fiber connector according to claim 5, wherein, The optical microscopic system is a ccd optical system.

7. The method of making a polarization maintaining fiber connector according to claim 6, wherein, The specific method of the in-situ heating in the step (3) is that, after the panda eye is positioned, the polarization maintaining optical fiber and the ferrule are not moved, and the polarization maintaining optical fiber connector is heated by using a heat source.

8. The method of making a polarization maintaining fiber connector according to any one of claims 1-7, wherein, In the step (4), the solidification temperature in the heating furnace is 80-200℃ and the solidification time is 8-60min.

9. The polarization maintaining optical fiber connector prepared by the manufacturing method in any one of claims 1-8.

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