A method for fabricating fiber optic arrays

Abstract

This invention relates to a method for fabricating an optical fiber array. The method involves placing a bare optical fiber within a V-groove on a substrate, and pressing a cover plate onto a portion of the bare fiber, exposing the section of the bare fiber between the front face of the substrate and the front face of the cover plate. The substrate, bare fiber, and cover plate are then bonded together using adhesive. A pressure block is placed on the exposed section of the bare fiber between the front face of the substrate and the front face of the cover plate, with the pressure block recessed within the front face of the substrate. A low-melting-point adhesive is used to bond the pressure block to the substrate, thus obtaining a semi-finished optical fiber array. A grinding disc is used to simultaneously grind the front face of the substrate and the end of the bare fiber in the semi-finished optical fiber array, shaping them into bevels with the desired angle. The low-melting-point adhesive is heated to detach the pressure block from the substrate, resulting in the finished optical fiber array. The beneficial effect is that the pressure block pressing down on the bare fiber significantly improves the yield of the optical fiber array during grinding.

Description

Technical Field

[0001] This invention relates to the field of fiber optic array technology, and more specifically to a method for fabricating a fiber optic array. Background Technology

[0002] The structure of common optical modules is as follows Figure 5 As shown, it includes: a PCB board, a fiber array, and an optical chip (PD chip). The fiber array includes: a substrate, a cover plate, and optical fibers. The substrate has V-grooves. From the perspective shown in the attached figure, the V-grooves can be formed on the lower surface of the substrate. The number of V-grooves on the substrate can be one, two, four, eight, etc. If the number of V-grooves is two or more, then all the V-grooves on the substrate are arranged side by side in an equally spaced manner. The V-grooves on the substrate penetrate through its front end face and rear end face. The bare optical fiber is located in the V-groove on the substrate. The cover plate is pressed on the bare optical fiber, and the substrate, bare optical fiber, and cover plate are bonded and fixed with adhesive. The adhesive can be UV adhesive. To ensure return loss, fiber optic arrays use 40°–45° fiber optic arrays, such as the common 42.5° fiber optic array. Figure 1 As shown, the front end face of the substrate and the end of the bare fiber in the fiber array are inclined surfaces of 40° to 45°. The cover plate in the fiber array is glued to the upper surface of the PCB board. The optical chip is located below the bare fiber in the fiber array and is coupled to the bare fiber in the fiber array. The optical chip is glued to the PCB board with silver paste. To achieve coupling efficiency, the bare fiber must be close enough to the optical chip, generally controlled within 30μm to 50μm. Therefore, a section of the bare fiber must be exposed (the cover plate only presses on a section of the bare fiber, while the section of the bare fiber between the front end face of the substrate and the front end face of the cover plate is exposed, that is, this section does not cover the cover plate). For the area where the substrate and the cover plate overlap, the substrate, the bare fiber and the cover plate are glued and fixed together. For the section of the bare fiber between the front end face of the substrate and the front end face of the cover plate, the bare fiber is glued and fixed to the substrate. To prevent the adhesive from adhering to the optical chip and silver paste, the cover plate generally does not completely cover the bare optical fiber; it is typically recessed by 0.7mm to 1mm. This leaves at least a 0.7mm section of the bare optical fiber exposed within the V-groove on the substrate. During the production of this type of fiber array, the front end face of the substrate in the semi-finished fiber array is planar, specifically as follows... Figure 2 As shown, a grinding disc is then used to simultaneously grind the front end face of the substrate and the end of the bare fiber in the fiber array semi-finished product, so as to grind the front end face of the substrate and the end of the bare fiber into a 40° to 45° bevel. Since at least 0.7 mm of the bare fiber is exposed, the exposed bare fiber is prone to delamination and detachment under stress during grinding. Specifically, as shown... Figure 4As shown, this leads to product defects, and it is difficult to control the amount of grinding during grinding. Excessive grinding not only wastes time but also causes the total length of the fiber array to be too short. Figure 3 As shown, the dashed line indicates excessive grinding. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for manufacturing fiber optic arrays to overcome the shortcomings of the prior art.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A method for fabricating a fiber optic array includes the following steps: S10. Place the bare optical fiber in the V-groove on the substrate, and press the cover plate on a section of the bare optical fiber so that the section of the bare optical fiber between the front end face of the substrate and the front end face of the cover plate is exposed. Then use glue to bond and fix the substrate, the bare optical fiber and the cover plate. S20. Press the pressure block onto the exposed section of the bare optical fiber between the front end face of the substrate and the front end face of the cover plate, with the pressure block recessed inside the front end face of the substrate. Use a low melting point adhesive to bond and fix the pressure block to the substrate to obtain a semi-finished fiber array. S30. A grinding disc is used to simultaneously grind the front end face of the substrate and the end of the bare optical fiber in the fiber array semi-finished product, so as to grind the front end face of the substrate and the end of the bare optical fiber into a bevel with the expected tilt angle. S40. Heat the low-melting-point adhesive to detach the compact from the substrate, thus obtaining the finished fiber optic array.

[0005] The beneficial effects of the present invention are: when the front end face of the substrate and the end of the bare optical fiber are simultaneously ground into a bevel with the expected tilt angle, since the pressure block presses on the exposed section of the bare optical fiber between the front end face of the substrate and the front end face of the cover plate, the pressure block can greatly disperse the force on the end of the bare optical fiber, so as to avoid the bare optical fiber in the exposed state from being debonded and falling off due to the force, thereby greatly improving the debonding yield of the optical fiber array during grinding.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

[0007] Furthermore, in S10, the end of the bare optical fiber is flush with the front face of the substrate.

[0008] Furthermore, the distance between the pressing block and the front end face of the substrate is 0.1mm to 0.15mm.

[0009] Furthermore, the front end face of the substrate and the end of the bare optical fiber are simultaneously ground into a bevel with an inclination angle of 40° to 45°.

[0010] Furthermore, the pressure block is made of metal, the grinding disc has an electrical feedback function, and the pressure block is clamped with a fixture that has an electrical feedback function. During the grinding process, when the pressure block is not in contact with the grinding disc, the electrical feedback is not triggered, the circuit is in an open circuit state, and the grinding disc continues to rotate. When the pressure block contacts the grinding disc, the electrical feedback is triggered, the circuit is in a short circuit state, the grinding disc stops, and the grinding process is automatically terminated.

[0011] The further beneficial effects of adopting the above are as follows: using electrical feedback to control the start and stop of the grinding disc can precisely control the amount of grinding, so as to avoid excessive grinding and save grinding time. At the same time, the length control of the fiber array is more precise, that is, it is easier to control the length of the fiber array.

[0012] Furthermore, the material of the briquette is a tungsten-copper alloy.

[0013] Furthermore, tungsten-copper alloy is W 90 Cu 10 .

[0014] Furthermore, during the polishing process, the angle between the substrate of the fiber array semi-finished product and the polishing disc is equal to the angle at which the front end face of the substrate and the end of the bare fiber are expected to be polished.

[0015] Furthermore, the low-melting-point adhesive is paraffin wax or pyrolytic adhesive.

[0016] The further beneficial effects of the above are: heating can soften the material and reduce its adhesive strength, thus making it easier to remove the pressure block;

[0017] Furthermore, the thickness of the pressure block is the same as the thickness of the cover plate. Attached Figure Description

[0018] Figure 1 This is a structural diagram of an optical fiber array before polishing in the prior art; Figure 2 This is a structural diagram of a fiber array after polishing in the prior art; Figure 3 This is a structural diagram of fiber array polishing in the prior art; Figure 4 This is a diagram showing the state of bare optical fibers debonding and detaching under stress during the polishing of optical fiber arrays in existing technologies. Figure 5 This is a structural diagram of a fiber optic array applied to an optical module in the prior art; Figure 6 This is a structural diagram of the fiber array semi-finished product before polishing in this invention; Figure 7 This is a structural diagram of the fiber array semi-finished product during polishing in this invention; Figure 8 This is a flowchart of the fiber optic array fabrication process in this invention.

[0019] The attached diagram lists the components represented by each number as follows: 1. Optical fiber, 110. Bare optical fiber, 2. Substrate, 3. Cover plate, 4. Press block, 5. Grinding disc. Detailed Implementation

[0020] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] Example 1 like Figure 6 , Figure 7 , Figure 8 As shown, a method for fabricating a fiber optic array includes the following steps: S10. Select a substrate 2 with a V-groove. The V-groove on the substrate 2 extends through its front and rear faces. As shown in the attached figure, the V-groove can be formed on the lower surface of the substrate 2. The number of V-grooves on the substrate 2 can be one, two, four, eight, etc. If the number of V-grooves is two or more, then all the V-grooves on the substrate 2 are arranged side by side with equal spacing. Place the bare optical fiber 110 of the optical fiber 1 in the V-groove on the substrate 2, and let the cover plate 3 press on a portion of the bare optical fiber 110. Ten sections are exposed between the front end face of the substrate 2 and the front end face of the cover plate 3, meaning that the cover plate 3 is not pressed into these sections. Then, adhesive is used to bond and fix the substrate 2, the bare optical fiber 110, and the cover plate 3. That is, for the overlapping area of ​​the substrate 2 and the cover plate 3, adhesive is used to bond and fix the substrate 2, the bare optical fiber 110, and the cover plate 3. For the section where the bare optical fiber 110 is located between the front end face of the substrate 2 and the front end face of the cover plate 3, the bare optical fiber 110 is bonded and fixed to the substrate 2 with adhesive. This part is still consistent with the existing technology. S20. Press the pressure block 4 onto the exposed section of the bare optical fiber 110 between the front end face of the substrate 2 and the front end face of the cover plate 3, and the pressure block 4 is recessed within the front end face of the substrate 2, that is: the pressure block 4 does not extend beyond the front end face of the substrate 2, and use a low melting point adhesive to bond and fix the pressure block 4 to the substrate 2 to obtain a fiber array semi-finished product. S30. The front end face of the substrate 2 and the end of the bare optical fiber 110 in the fiber array semi-finished product are polished simultaneously using the polishing disc 5, so as to polish the front end face of the substrate 2 and the end of the bare optical fiber 110 into the expected angle of inclination. During polishing, the substrate 2 first contacts the polishing disc 5. S40. Heat the low-melting-point adhesive to detach the pressure block 4 from the substrate 2, thus obtaining the finished fiber optic array.

[0022] When the front end face of the substrate 2 and the end of the bare optical fiber 110 are simultaneously ground into a bevel with the expected tilt angle, the pressure block 4 presses on the exposed section of the bare optical fiber 110 between the front end face of the substrate 2 and the front end face of the cover plate 3. Therefore, the pressure block 4 can greatly disperse the force on the end of the bare optical fiber 110, so as to avoid the bare optical fiber 110 in the exposed state from being debonded and falling off due to the force, which greatly improves the debonding yield of the optical fiber array during grinding.

[0023] Example 2 like Figure 7 , Figure 8 As shown, this embodiment is a further improvement on embodiment 1, as detailed below: In S10, the end of the bare optical fiber 110 is preferably flush with the front end surface of the substrate 2, which is consistent with the existing technology.

[0024] Example 3 like Figure 7 , Figure 8 As shown, this embodiment is a further improvement on embodiment 1 or 2, as detailed below: The distance between the pressure block 4 and the front end face of the substrate 2 is 0.1mm to 0.15mm, so as to ensure that the end of the bare optical fiber 110 is ground into a slope with the expected tilt angle, and the slope formed by grinding the end of the bare optical fiber 110 is a total reflection surface.

[0025] Furthermore, the front end face of the substrate 2 and the end of the bare optical fiber 110 are simultaneously ground into a bevel with an inclination angle of 40° to 45°, for example, it can be the common 42.5°, of course, this is just an exemplary example.

[0026] Example 4 like Figure 7 , Figure 8 As shown, this embodiment is a further improvement on embodiment 1, 2, or 3, as detailed below: The pressure block 4 is made of metal, the grinding disc 5 has an electrical feedback function, and the pressure block 4 is clamped with a fixture that also has an electrical feedback function. Figure 8 The arrow pointing to the pressure block 4 indicates the fixture; during the grinding process, when the pressure block 4 is not in contact with the grinding disk 5, the electrical feedback is not triggered, the circuit is in an open circuit state, and the grinding disk 5 continues to rotate to carry out the grinding work. When the pressure block 4 contacts the grinding disk 5, the electrical feedback is triggered, the circuit is in a short circuit state, the grinding disk 5 stops, and the grinding is automatically terminated. Using the electrical feedback method to control the start and stop of the grinding disk 5 can precisely control the amount of grinding, so as to avoid excessive grinding and save grinding time. At the same time, the length control of the fiber array is more precise, that is, it is easier to control the length of the fiber array.

[0027] Furthermore, the material of the pressing block 4 is preferably a tungsten-copper alloy, and the tungsten-copper alloy is preferably W.90 Cu 10 The tungsten copper alloy surface is plated with nickel to prevent rusting.

[0028] Example 5 like Figure 7 , Figure 8 As shown, this embodiment is a further improvement on embodiment 1, 2, 3, or 4, as detailed below: During the polishing process, the angle between the substrate 2 and the polishing disc 5 of the fiber array semi-finished product is equal to the expected angle of polishing of the front end face of the substrate 2 and the end of the bare fiber 110. For example, if the angle of simultaneous polishing of the front end face of the substrate 2 and the end of the bare fiber 110 is 40° to 45°, then the angle between the substrate 2 and the polishing disc 5 of the fiber array semi-finished product during the polishing process is 40° to 45°. During the polishing process, the fiber array semi-finished product is held by a fixture. Figure 8 The arrow pointing to the base plate 2 and the cover plate 3 indicates the fixture.

[0029] The low-melting-point adhesive is paraffin wax (a mixture of paraffin wax and rosin), which balances hardness / toughness and adhesion. Paraffin wax has a low melting point (less than 100°C), can be softened by heating, and its adhesion decreases, thus making it easy to remove the pressure block 4. The thickness of the pressure block 4 is preferably the same as the thickness of the cover plate 3. Alternatively, the low-melting-point adhesive is a pyrolytic adhesive. When the pyrolytic adhesive bonds and fixes the pressing block 4 to the substrate 2, it is cured by UV irradiation. After grinding, the pyrolytic adhesive is heated to 100°C and the adhesive automatically falls off.

[0030] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for fabricating an optical fiber array, characterized in that, Includes the following steps: S10. Place the bare optical fiber (110) of the optical fiber (1) in the V groove on the substrate (2) and press the cover plate (3) on a section of the bare optical fiber (110) so that the section of the bare optical fiber (110) between the front end face of the substrate (2) and the front end face of the cover plate (3) is exposed. Then use glue to bond and fix the substrate (2), the bare optical fiber (110) and the cover plate (3). S20. Press the pressure block (4) onto the exposed section of the bare optical fiber (110) between the front end face of the substrate (2) and the front end face of the cover plate (3), and retract the pressure block (4) into the front end face of the substrate (2), and use a low melting point adhesive to bond and fix the pressure block (4) to the substrate (2) to obtain a fiber array semi-finished product. S30. The front end face of the substrate (2) and the end of the bare optical fiber (110) in the fiber array semi-finished product are simultaneously ground using a grinding disc (5) to grind the front end face of the substrate (2) and the end of the bare optical fiber (110) into a slope with the expected tilt angle. S40. Heat the low-melting-point adhesive to detach the compact (4) from the substrate (2) to obtain the finished fiber array.

2. The method for fabricating an optical fiber array according to claim 1, characterized in that, The end of the bare optical fiber (110) in S10 is flush with the front end face of the substrate (2).

3. A method for fabricating an optical fiber array according to claim 1 or 2, characterized in that, The distance between the pressure block (4) and the front end face of the substrate (2) is 0.1mm to 0.15mm.

4. A method for fabricating an optical fiber array according to claim 1, 2, or 3, characterized in that, The front end face of the substrate (2) and the end of the bare optical fiber (110) are simultaneously ground into a slope with an inclination angle of 40° to 45°.

5. The method for fabricating an optical fiber array according to claim 1, characterized in that, The pressure block (4) is made of metal, the grinding disc (5) has an electrical feedback function, and the pressure block (4) is clamped with a fixture that has an electrical feedback function. During the grinding process, when the pressure block (4) does not contact the grinding disc (5), the electrical feedback is not triggered, the circuit is in an open circuit state, the grinding disc (5) continues to rotate, and when the pressure block (4) contacts the grinding disc (5), the electrical feedback is triggered, the circuit is in a short circuit state, the grinding disc (5) stops, and the grinding is automatically terminated.

6. The method for fabricating an optical fiber array according to claim 1, characterized in that, The material of the pressing block (4) is tungsten copper alloy.

7. The fiber optic array fabrication method according to claim 6, characterized in that, The tungsten-copper alloy is W 90 Cu 10 .

8. The method for fabricating an optical fiber array according to claim 1, characterized in that, During the polishing process, the angle between the substrate (2) of the fiber array semi-finished product and the polishing disc (5) is equal to the angle at which the front end face of the substrate (2) and the end of the bare fiber (110) are expected to be polished.

9. The method for fabricating an optical fiber array according to claim 1, characterized in that, Low-melting-point adhesives are paraffin wax or pyrolytic adhesives.

10. A method for fabricating an optical fiber array according to claim 1, characterized in that, The thickness of the pressure block (4) is the same as the thickness of the cover plate (3).

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