A coupling method for the optical emission submodule of a dual-lens system

Abstract

This invention belongs to the field of optical communication technology and relates to a coupling method for an optical transmitting submodule of a dual-lens system. First, the laser, isolator, and fiber optic adapter are passively fixed. Then, the position of the focusing lens is fixed in the X-axis direction, and its positions in the Y-axis and Z-axis directions are pre-fixed in an active environment. Next, the positions of the collimating lens in the X-axis, Y-axis, and Z-axis directions are pre-fixed in an active environment. Then, the focusing lens is moved along the positive Y-axis, negative Y-axis, positive Z-axis, and negative Z-axis directions, and the position of the collimating lens is adjusted accordingly to maximize the optical power output from the fiber optic adapter. This determines and fixes the position of the focusing lens. Finally, the position of the collimating lens is adjusted to maximize the optical power and then fixed, thus completing the coupling. This coupling method can reduce the influence of positional deviations of the laser and fiber optic adapter, improving the coupling efficiency of the product.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and more specifically to a coupling method for an optical emission submodule of a dual-lens system. Background Technology

[0002] With the rapid development of 5G communication and the increasing demand from data centers, the market demand for optical modules such as 10G, 25G, 100G, and 400G is growing. Especially when laser output power is limited, the requirements for optical coupling efficiency are becoming increasingly stringent. The coupling method of the optical emitting component determines the optical coupling efficiency. Therefore, choosing the right coupling method to ensure optimal coupling efficiency is becoming increasingly crucial, thereby improving product yield and achieving lower costs.

[0003] The optical components of the optical modules we typically use employ a dual-lens system. Figure 1 It is a typical single-path dual-lens system. The most basic components include a laser, collimating lens, converging lens, and fiber optic adapter. There are usually other auxiliary components such as TEC and optical isolators. Optical modules typically have certain requirements for output optical power. Therefore, maximizing coupling efficiency becomes very important and directly determines the yield of the finished product.

[0004] The main steps of the traditional coupling method are as follows:

[0005] 1) First, attach the laser, assemble the fiber optic adapter, and connect the laser to the PCB board using gold wire bonding. Then, power on the laser to light it up.

[0006] 2) Fix the distance between the converging lens and the fiber optic adapter and adjust the positions in the other two directions to maximize the light output from the fiber optic adapter, then fix the position of the converging lens with glue.

[0007] 3) Take a collimating lens and adjust its position in three directions to maximize the light output from the fiber optic adapter. Then, fix the position of the collimating lens with glue.

[0008] However, in this traditional coupling method, deviations in the laser patch position and angle can cause positional deviations during coupling by the converging lens, resulting in reduced coupling efficiency or even coupling failure. Summary of the Invention

[0009] The purpose of this invention is to provide a coupling method for the optical emission sub-module of a dual-lens system, which can at least solve some of the defects in the prior art.

[0010] To achieve the above objectives, the technical solution of the present invention is a coupling method for the optical emission sub-module of a dual-lens system, comprising the following steps:

[0011] S1. After fixing the laser, isolator, and fiber optic adapter, power on the laser to turn it on.

[0012] S2. Fix the position of the converging lens in the X-axis direction at a distance f from the fiber optic adapter, and then adjust the position of the converging lens in the Y-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter.

[0013] S3. Place the collimating lens between the laser and the converging lens, and adjust the position of the collimating lens in the X-axis, Y-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter and record the optical power value P0 at this time.

[0014] S4. Move the focusing lens a certain distance d along the positive Y-axis, then readjust the position of the collimating lens and make the optical power output from the fiber optic adapter reach its maximum. Record the optical power value P1 at this time and compare the magnitudes of P1 and P0.

[0015] If P1 is significantly greater than P0, return to step S4 and refresh the value of P0 with the value of P1; if P1 is significantly less than P0, jump to step S5 and refresh the value of P0 with the value of P1; if P1 is close to P0, jump to step S6.

[0016] S5. Move the focusing lens a certain distance d in the opposite direction of the Y-axis, then readjust the position of the collimating lens and make the optical power output from the fiber optic adapter reach the maximum. Record the optical power value P1 at this time, and determine whether P1 is significantly greater than P0. If so, return to step S5 and refresh the value of P0 with the value of P1 at the same time; otherwise, jump to step S6.

[0017] S6. Move the focusing lens a certain distance along the positive Z-axis, then readjust the position of the collimating lens and make the optical power output from the fiber optic adapter reach its maximum. Record the optical power value P2 at this time and compare the magnitude of P2 with P1.

[0018] If P2 is significantly greater than P1, return to step S6 and refresh the value of P1 with the value of P2; if P2 is significantly less than P1, jump to step S7 and refresh the value of P1 with the value of P2; if P2 is close to P1, jump to step S8.

[0019] S7. Move the focusing lens a certain distance in the opposite direction of the Z-axis, then readjust the position of the collimating lens and make the optical power output from the fiber optic adapter reach the maximum. Record the optical power value P2 at this time, and determine whether P2 is significantly greater than P1. If so, return to step S7; otherwise, jump to step S8.

[0020] S8. Record the position of the converging lens at this time, and fix the position of the converging lens;

[0021] S9. By monitoring the optical power coming out of the fiber optic adapter, adjust the position of the collimating lens to maximize the optical power, and then fix the position of the collimating lens.

[0022] S10. Complete the coupling and further bake and cure the finished product.

[0023] Furthermore, in step S1, one end of the optical output port of the optical fiber adapter is connected to the optical power meter through a single-mode optical fiber, and the optical power output from the optical fiber adapter is detected by the optical power meter.

[0024] Furthermore, in step S2, the distance f between the position of the converging lens in the X-axis direction and the fiber optic adapter is the focal length of the converging lens.

[0025] Furthermore, in steps S4-S7, an increase in optical power greater than 1% is defined as significantly greater than, a decrease in optical power greater than 1% is defined as significantly less than, and an absolute change in optical power less than or equal to 1% is defined as close to.

[0026] Further, in step S8, UV adhesive is applied to the converging lens and UV cured to fix the position of the converging lens.

[0027] Further, in step S9, UV adhesive is applied to the collimating lens, and after adjusting the position of the collimating lens to maximize the optical power, the collimating lens is raised to a predetermined height along the positive Y-axis, and then UV-cured to fix the position of the collimating lens.

[0028] Furthermore, the collimating lens is tilted upwards along the positive Y-axis by a height of 0.5–0.7 μm.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) In this invention, the laser, isolator, and fiber optic adapter are first passively fixed. Then, the position of the focusing lens in the X-axis direction is fixed, and the position of the focusing lens in the Y-axis and Z-axis directions is pre-fixed in an active environment. Then, the position of the collimating lens in the X-axis, Y-axis, and Z-axis directions is pre-fixed in an active environment. Next, the focusing lens is moved along the positive Y-axis, the negative Y-axis, the positive Z-axis, and the negative Z-axis, and the position of the collimating lens is adjusted accordingly to maximize the optical power output from the fiber optic adapter. This determines and fixes the position of the focusing lens. After adjusting the position of the collimating lens to maximize the optical power, it is fixed, thus completing the coupling. This can greatly reduce the impact of laser position deviation and angle deviation on the coupling position deviation of the focusing lens, improve coupling efficiency, and completely avoid the problem of coupling failure.

[0031] (2) In this invention, when applying UV glue to the collimating lens and adjusting the position of the collimating lens to maximize the optical power, the collimating lens is raised to a predetermined height along the positive Y-axis, and then UV-cured to fix the position of the collimating lens. This can compensate for the shrinkage of the heat-curing glue after UV curing, and ensure that after the next baking and curing step, the collimating lens is fixed at the position where the optical power output of the fiber optic adapter is the maximum. Attached Figure Description

[0032] 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.

[0033] Figure 1 This is a typical single-path dual-lens system;

[0034] Figure 2 This is a diagram defining the movement direction of the dual-lens system provided in an embodiment of the present invention;

[0035] Figure 3 A flowchart illustrating the coupling method of the optical emission sub-module of the dual-lens system provided in an embodiment of the present invention;

[0036] In the diagram: 1. Laser; 2. Collimating lens; 3. Converging lens; 4. Isolator; 5. Fiber optic adapter; 6. Device housing. Detailed Implementation

[0037] 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.

[0038] like Figures 2-3 As shown, this embodiment provides a coupling method for the optical emission sub-module of a dual-lens system, including the following steps:

[0039] S1. Fix the laser 1, isolator 4, and fiber optic adapter 5 to the device housing 6 in advance, and connect the laser 1 to the wire bonding pad on the device housing 6 by gold wire bonding. Then power on the laser 1 to light it up. Connect one end of the optical output port of the fiber optic adapter 5 to the optical power meter through a single-mode optical fiber. Monitor the optical power output from the fiber optic adapter 5 through the optical power meter.

[0040] S2. Take a converging lens 3 and fix its position in the X-axis direction at a certain distance from the fiber optic adapter 5. Specifically, the distance between the converging lens 3 and the fiber optic adapter 5 in the X-axis direction is the focal length of the converging lens 3. Then adjust the position of the converging lens 3 in the Y-axis and Z-axis directions to maximize the optical power output from the fiber optic adapter 5.

[0041] S3. Take out a collimating lens 2, place the collimating lens 2 between the laser 1 and the converging lens 3, adjust the position of the collimating lens 2 in the three directions of X-axis, Y-axis and Z-axis so that the optical power output from the fiber optic adapter 5 reaches the maximum and record the optical power value P0 at this time.

[0042] S4. Move the converging lens 3 a certain distance d along the positive Y-axis (d is the step of the converging lens movement), then readjust the position of the collimating lens 2 and make the optical power output from the fiber optic adapter 5 reach the maximum. Record the optical power value P1 at this time and compare the magnitude of P1 with P0.

[0043] If P1 is significantly greater than P0, return to step S4 and refresh the value of P0 with the value of P1; if P1 is significantly less than P0, jump to step S5 and refresh the value of P0 with the value of P1; if P1 is close to P0, jump to step S6.

[0044] S5. Move the focusing lens 3 a certain distance d in the opposite direction of the Y-axis, then readjust the position of the collimating lens 2 and make the optical power output from the fiber optic adapter 5 reach the maximum. Record the optical power value P1 at this time, and determine whether P1 is significantly greater than P0. If so, return to step S5 and refresh the value of P0 with the value of P1. Otherwise, jump to step S6.

[0045] S6. Move the focusing lens 3 a certain distance d along the positive Z-axis, then readjust the position of the collimating lens 2 and make the optical power output from the fiber optic adapter 5 reach the maximum. Record the optical power value P2 at this time and compare the magnitude of P2 with P1.

[0046] If P2 is significantly greater than P1, return to step S6 and refresh the value of P1 with the value of P2; if P2 is significantly less than P1, jump to step S7 and refresh the value of P1 with the value of P2; if P2 is close to P1, jump to step S8.

[0047] S7. Move the focusing lens 3 a certain distance d in the opposite direction of the Z-axis, then readjust the position of the collimating lens 2 and make the optical power output from the fiber optic adapter 5 reach the maximum. Record the optical power value P2 at this time, and determine whether P2 is significantly greater than P1. If P2 is significantly greater than P1, return to step S7 and refresh the P1 value with the P2 value at the same time. Otherwise, jump to step S8.

[0048] S8. Record the position of the converging lens 3 at this time, apply UV glue to the converging lens 3 and UV cure to fix the position of the converging lens 3;

[0049] S9. Apply UV adhesive to collimating lens 2. By monitoring the optical power output from fiber optic adapter 5, adjust the position of collimating lens 2 to maximize the optical power. Then, raise collimating lens 2 upward along the positive Y-axis to a predetermined height, and then UV cure to fix the position of collimating lens 2. Specifically, the height raised by the collimating lens upward along the positive Y-axis is 0.5 to 0.7 μm, optimized to 0.6 μm, to compensate for the shrinkage of the thermosetting adhesive after UV curing, ensuring that after the next baking and curing step, collimating lens 2 is fixed at the position where the optical power output from fiber optic adapter 5 is maximized.

[0050] S10. Complete the coupling and place the finished product in the oven for further baking and curing.

[0051] In steps S4-S7 above, an increase in optical power greater than 1% is defined as significantly greater than, a decrease in optical power greater than 1% is defined as significantly less than, and an absolute change in optical power less than or equal to 1% is defined as close to.

[0052] In steps S4-S7 above, the distance d that the converging lens 3 moves each time is the step size of the converging lens 3, which is generally 1-2 μm, and the step size in each step may be different.

[0053] In this embodiment, the laser 1, isolator 4, and fiber optic adapter 5 are first passively fixed. Then, the position of the focusing lens 3 in the X-axis direction is fixed, and the positions of the focusing lens 3 in the Y-axis and Z-axis directions are pre-fixed in an active environment. After that, the positions of the collimating lens 2 in the X-axis, Y-axis, and Z-axis directions are pre-fixed in an active environment. Then, the focusing lens 3 is moved sequentially along the positive Y-axis, the negative Y-axis, the positive Z-axis, and the negative Z-axis, and the position of the collimating lens 2 is adjusted accordingly to maximize the optical power output from the fiber optic adapter 5. This determines and fixes the position of the focusing lens 3. After that, the position of the collimating lens 2 is adjusted to maximize the optical power and then fixed, thus completing the coupling. This greatly reduces the impact of laser position deviation and angle deviation on the coupling position of the focusing lens, improves coupling efficiency, and completely avoids the occurrence of coupling failure.

[0054] 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 coupling a dual lens system optical transmitter subassembly, comprising: The method comprises the following steps: S1, after fixing the laser, isolator and fiber adapter, power on the laser to light up the laser; S2, fix the position of the converging lens in the X-axis direction at a distance f from the fiber adapter, then adjust the positions of the converging lens in the Y-axis and Z-axis directions to make the light power output from the fiber adapter reach the maximum; S3, place the collimating lens between the laser and the converging lens, adjust the positions of the collimating lens in the X-axis, Y-axis and Z-axis directions to make the light power output from the fiber adapter reach the maximum, and record the light power value P0 at this time; S4, move the converging lens in the positive direction of the Y-axis by a certain distance, then re-adjust the position of the collimating lens to make the light power output from the fiber adapter reach the maximum, record the light power value P1 at this time, and compare the values of P1 and P0; If P1 is significantly greater than P0, return to step S4, and refresh the value of P0 with the value of P1; if P1 is significantly less than P0, jump to step S5, and refresh the value of P0 with the value of P1; if P1 is close to P0, jump to step S6; S5, move the converging lens in the reverse direction of the Y-axis by a certain distance, then re-adjust the position of the collimating lens to make the light power output from the fiber adapter reach the maximum, record the light power value P1 at this time, and determine whether P1 is significantly greater than P0; if yes, return to step S5, and refresh the value of P0 with the value of P1; if no, jump to step S6; S6, move the converging lens in the positive direction of the Z-axis by a certain distance, then re-adjust the position of the collimating lens to make the light power output from the fiber adapter reach the maximum, record the light power value P2 at this time, and compare the values of P2 and P1; If P2 is significantly greater than P1, return to step S6, and refresh the value of P1 with the value of P2; if P2 is significantly less than P1, jump to step S7, and refresh the value of P1 with the value of P2; if P2 is close to P1, jump to step S8; S7, move the converging lens in the reverse direction of the Z-axis by a certain distance, then re-adjust the position of the collimating lens to make the light power output from the fiber adapter reach the maximum, record the light power value P2 at this time, and determine whether P2 is significantly greater than P1; if yes, return to step S7; if no, jump to step S8; S8, record the position of the converging lens at this time, and fix the position of the converging lens; S9, adjust the position of the collimating lens to make the light power reach the maximum by monitoring the light power output from the fiber adapter, and then fix the position of the collimating lens; S10, complete the coupling and further bake and solidify the finished product.

2. The method of claim 1, wherein the lens system is a dual lens system. In step S1, connect the light outlet end of the fiber adapter with the optical power meter through a single-mode optical fiber, and detect the light power output from the fiber adapter through the optical power meter.

3. The method of claim 1, wherein: the lens system is a dual lens system; and the optical transmitter subassembly is a dual lens system optical transmitter subassembly. In step S2, the distance f between the position of the converging lens in the X-axis direction and the fiber adapter is the focal length of the converging lens.

4. The method of claim 1, wherein the lens system is a dual lens system. In steps S4-S7, when the light power increases by more than 1%, it is defined as significantly greater; when the light power decreases by more than 1%, it is defined as significantly less; and when the absolute value of the change in light power is less than or equal to 1%, it is defined as close.

5. The method of claim 1, wherein: the lens system is a dual lens system; and the optical subassembly is a dual lens system optical subassembly. In step S8, UV glue is applied to the converging lens and UV cured to fix the position of the converging lens.

6. The coupling method of the optical emission sub-module of the dual-lens system as described in claim 1, characterized in that: In step S9, UV glue is applied to the collimating lens, and after the position of the collimating lens is adjusted to maximize the optical power, the collimating lens is lifted by a predetermined height in the positive direction of the Y axis, and then UV cured to fix the position of the collimating lens.

7. The coupling method of the dual-lens system optical subassembly as claimed in claim 6, wherein: The height by which the collimating lens is lifted in the positive direction of the Y axis is 0.5-0.7 μm.

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