A coupling method for multiplexed optical receiving submodule

Abstract

The present invention relates to the field of optical communication technology, and provides a coupling method for a multiplexed optical receiving submodule, comprising the following steps: S1, fixing an optical element in a device housing in a passive manner, setting an optical fiber adapter outside the device housing, and completing electrical connection by punching a gold wire; S2, fixing a standard part with four PDs arranged in a line on a machine platform; S3, fixing a product to be coupled with collimated light on the machine platform, and also loading an optical component with four semi-reflective lenses into the device housing and positioning it; S4, connecting a red light source to the optical fiber adapter; S5, when adjusting the position of the collimating lens, observing the position and size of four red light spots on the PD from a computer screen through a CCD, determining the final position of the collimating lens, and thus completing the coupling of the collimating lens. The present invention uses red light to assist coupling, and since red light is visible light, it is very intuitive to observe the light spot during coupling, and the operation is simple.

Description

Technical Field

[0001] The invention relates to the technical field of optical communications, and in particular to a coupling method for a multiplexed optical receiving submodule. Background Art

[0002] With the development of the optical communication industry, the amount of data that needs to be transmitted is increasing, so the transmission rate requirements for optical modules are also increasing. In recent years, the technology of multiplexing multiple wavelengths of light directly into one in the optical module and then transmitting it in the optical fiber has become more and more widely used. Typical products include 4*10G, 4*25G single-mode products that have been shipped in large quantities, and 4*50G, 4*100G single-mode products whose shipments are currently growing rapidly. Compared with traditional coaxial products, multiplexed products are more complex in structure and optical path design, and the optical coupling process is more difficult. The type of optical coupling method adopted will directly determine the success rate of optical coupling and the yield of the product.

[0003] Figure 1 This is a typical structure and optical path diagram of a 4-way multiplexed optical receiver submodule (ROSA). A ROSA usually includes a device housing, a TIA (transimpedance amplifier), 4 PDs (photodiodes), 4 focusing lenses that focus light onto the PDs, a DMUX (optical demultiplexer), a collimating lens that collimates the light coming out of the adapter, and a fiber adapter.

[0004] Typically, this 4-way multiplexed ROSA couples the optical signal received by the adapter into 4 PDs. The coupling steps are as follows:

[0005] 1. Passive paste TIA, PD, DMUX and other components on the housing;

[0006] 2. Use glue or laser welding to fix the adapter to the housing;

[0007] 3. Make gold wires for TIA and PD in the shell;

[0008] 4. Connect the light source to the adapter, adjust the collimating lens, collimate the light coming out of the adapter, and then fix the collimating lens;

[0009] 5. Connect the light source to the adapter, power on the TIA and PD, adjust the positions of the four converging lenses in sequence to couple the light into the PD, and then fix the converging lenses with glue to complete the coupling.

[0010] The schematic diagram of fixing the collimating lens when collimating the light from the adapter is as follows Figure 2 As shown, a displacement prism is usually used to guide the collimated light to the outside of the light receiving submodule, the position of the light spot is monitored by the CCD, and then the position of the collimating lens is adjusted to adjust the collimated light spot to a pre-specified position.

[0011] The traditional optical coupling method has the following disadvantages:

[0012] 1. If Figure 2 As shown, when the light coming out of the adapter is collimated with a collimating lens, a prism is needed to lead the collimated light out of the housing and an external CCD lens or infrared imager is used to monitor the light spot of the collimated light for adjustment to determine whether the light coming out after passing through the collimating lens is collimated. This coupling method requires an external high-speed lens and prism, which results in a complex equipment structure, high cost, and great coupling difficulty.

[0013] 2. The position of the collimated light spot depends on the calibration of the machine, or more precisely, on the fixed position of the high-speed lens. If there is a deviation in the fixed position of the high-speed lens, the coupled collimated light will also have a deviation, thereby affecting the coupling efficiency of the light coupled into the PD by the subsequent converging lens;

[0014] 3. The position of the collimated light spot also depends on the position of the shell on the coupling table. If there is a deviation in the assembly of the shell on the coupling table, the final collimated light path will also have a deviation, thereby affecting the coupling efficiency of the light coupled into the PD by the subsequent converging lens;

[0015] 4. After the collimated light spot is coupled, there will be deviations in the mounting positions of the triangular prism and PD of different products. This coupling method cannot take the mounting position deviation of the PD and the triangular prism into account when coupling the collimating lens, which will also have a relatively large impact on the coupling efficiency. Summary of the invention

[0016] The object of the present invention is to provide a coupling method for a multiplexed optical receiving submodule, which can at least solve some of the defects in the prior art.

[0017] To achieve the above object, an embodiment of the present invention provides the following technical solution: a coupling method of a multiplexed optical receiving sub-module, comprising the following steps:

[0018] S1, fix the optical element in the device housing in a passive way, set a fiber optic adapter outside the device housing, and make a gold wire to complete the electrical connection;

[0019] S2, fix the standard component with four PDs arranged in a line on the machine table;

[0020] S3, fix the product to be coupled with collimated light on the machine table, and also install the optical component with four semi-reflective lenses into the device housing and position it;

[0021] S4, connecting the optical fiber adapter to a red light source;

[0022] S5, when adjusting the position of the collimating lens, the positions and sizes of the four red light spots on the PD are observed on the computer screen through the CCD to determine the final position of the collimating lens, thereby completing the coupling of the collimating lens.

[0023] Furthermore, the specific steps of adjusting the red light spot are as follows:

[0024] On the screen, take the center of the photosensitive surface of the PD of the standard part as the center of the circle and R as the radius to draw four reference circles on the computer screen as reference positions. The value of R is between 150 and 300 μm.

[0025] Adjust the four red light spots projected onto the four PDs to be within the four circles;

[0026] Adjust the position of the collimating lens along the Z-axis direction, select one of the channels, and adjust its spot size to a predetermined size;

[0027] Adjust the position of the collimating lens along the X-axis and Y-axis directions so that the centers of the photosensitive surfaces of the first and last channels PD coincide with the centers of the corresponding red light spots.

[0028] Furthermore, the positioning method of the optical component is specifically as follows: a positioning surface is pre-arranged in the device housing, and when the optical component is placed in the device housing, the optical component is closely attached to the positioning surface, thereby completing the precise positioning of the optical component.

[0029] Furthermore, after the position of the collimating lens is determined, UV glue is applied to the collimating lens and the UV glue is cured to complete the coupling of the collimating lens.

[0030] Furthermore, after the coupling of the collimating lens is completed, the optical component is removed for coupling with the collimating lens of the next product.

[0031] Furthermore, the optical multiplexing component is then passively attached to the device housing and fixed.

[0032] Furthermore, the product to be coupled with the converging lens is fixed on the machine platform, the PD is powered on, a converging lens is grabbed and moved to one of the channels, and the position of the converging lens is adjusted to maximize the responsiveness of the PD of the corresponding channel.

[0033] Furthermore, after the converging lens is adjusted, the converging lens is fixed.

[0034] Furthermore, another converging lens is repeatedly grabbed and moved to another channel, the position of the converging lens is adjusted to maximize the responsiveness of the corresponding channel PD, and the converging lens is fixed until all channel converging lenses are coupled.

[0035] Furthermore, after all the optical components are coupled, the product is placed in an oven to further cure the glue.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. Use red light to assist coupling. Since red light is visible light, it is very intuitive to observe the light spot during coupling, and the operation is simple.

[0038] 2. The position of the red light spot is directly related to the actual position of the PD, which greatly reduces the impact of the PD mounting position deviation on the coupling efficiency and improves the final coupling efficiency.

[0039] 3. When fixing the collimating lens, the triangular prism has been attached, which greatly reduces the influence of the position deviation of the triangular prism on the coupling efficiency and improves the coupling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the optical path of a typical optical receiving submodule (ROSA);

[0041] Figure 2 Schematic diagram of a typical ROSA (receiver optical submodule) with a fixed collimating lens;

[0042] Figure 3 A schematic diagram of a multiplexed optical receiving sub-module provided by an embodiment of the present invention;

[0043] Figure 4 A schematic diagram of a PD photosensitive surface and a reference circle on a screen in a method for coupling a collimating lens of a multiplexed light receiving submodule provided by an embodiment of the present invention;

[0044] Figure 5 A schematic diagram of the positions of a red light spot and a reference circle in a method for coupling a collimating lens of a multiplexed light receiving submodule provided in an embodiment of the present invention;

[0045] Figure 6 A schematic diagram of the adjustment of the light spot size in a coupling method of a collimating lens of a multiplexed light receiving sub-module provided by an embodiment of the present invention;

[0046] Figure 7 A schematic diagram of the adjustment of the light spot position in a coupling method of a collimating lens of a multiplexed light receiving sub-module provided by an embodiment of the present invention;

[0047] In the accompanying drawings: 1-PD; 2-triangular prism; 3-converging lens; 4-collimating lens; 5-device housing; 6-optical fiber adapter; 7-optical element. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] See also Figure 3 , the embodiment of the present invention provides a coupling method for a multiplexed optical receiving submodule, comprising the following steps: S1, fix the optical element in a device housing 5 in a passive manner, set an optical fiber adapter 6 outside the device housing 5, and complete the electrical connection by punching gold wire; S2, fix the standard part with four PD1s arranged in a line on the machine; S3, fix the product to be coupled with collimated light on the machine, and also install the optical component with four semi-reflective lenses in the device housing 5 and position it; S4, connect the optical fiber adapter 6 with a red light source; S5, when adjusting the position of the collimating lens 4, observe the position and size of the four red light spots on the PD1 from the computer screen through the CCD (CCD is connected to the computer screen), determine the final position of the collimating lens 4, and thus complete the coupling of the collimating lens 4. In this embodiment, red light is used to assist coupling. Since red light is visible light, it is very intuitive to observe the light spot during coupling, and the operation is simple; the position of the red light spot is directly related to the actual position of PD1, which greatly reduces the influence of the PD1 mounting position deviation on the coupling efficiency and improves the final coupling efficiency.

[0050] As an optimization solution of the embodiment of the present invention, please refer to Figure 4 , Figure 5 , Figure 6 and Figure 7 , the specific steps of adjusting the red light spot are as follows: on the screen, with the center of the photosensitive surface of the standard PD1 as the center of the circle, and R as the radius, four reference circles are drawn on the computer screen as reference positions, and the value of R is between 150 and 300 μm; the four red light spots projected on the four PD1 are adjusted to be within the four circles; the position of the collimating lens 4 along the Z axis direction is adjusted, and one of the channels is selected to adjust its spot size to a predetermined size; the position of the collimating lens 4 along the X axis and Y axis directions is adjusted so that the center of the photosensitive surface of the first and last two channels PD1 coincides with the center of the red light spot corresponding to them. In this embodiment, Figure 4 As shown, on the screen, with the center of the photosensitive surface of the standard PD1 as the center of the circle and R as the radius, four reference circles are drawn on the computer screen as reference positions, and the value of R is between 150um and 300um; Figure 5 As shown, the four red light spots projected from the optical component to the PD1 through the triangular prism 2 are adjusted to be within the four circles; Figure 6As shown, adjust the position of the collimating lens 4 along the Z-axis direction, and adjust the spot size of the channel with the longest optical path (other channels can also be selected) to a predetermined size (for example, 150um, the size of this spot is determined according to the actual situation, the purpose is to make the diameter of the red light spot on the four PD1 near 150um and as consistent as possible); Figure 7 As shown, adjust the position of the collimating lens 4 along the X-axis and Y-axis directions so that the centers of the two red light spots on the side coincide with the centers of the photosensitive surfaces of the two channel PD1 on the side. Finally, glue is dispensed to the collimating lens 4 and UV cured to fix the collimating lens 4, thus completing the coupling of the collimating lens 4.

[0051] As an optimization solution of the embodiment of the present invention, please refer to Figure 3 The positioning method of the optical component is specifically as follows: a positioning surface is pre-set in the device housing 5, and when the optical component is placed in the device housing 5, the optical component is closely attached to the positioning surface, thereby completing the precise positioning of the optical component. In this embodiment, positioning by the positioning surface can improve the positioning efficiency.

[0052] As an optimization solution of the embodiment of the present invention, the following is a coherent coupling method, first coupling the collimating lens 4, and then coupling other optical elements:

[0053] (1) Fix the components such as PD1, TIA, triangular prism 2, optical fiber adapter 6 in the device housing 5 in a passive manner, and use gold wire to complete the electrical connection of PD1, TIA, etc.;

[0054] (2) Fix the standard part (the standard part has four PD1s and a triangular prism 2 attached, which is mainly used to calibrate the position of PD1 on the screen) on the machine table, and draw four reference circles on the screen with the photosensitive surface of PD1 as the center and R = 250 μm as the radius;

[0055] (3) Fix the product to be coupled with collimated light on the machine platform and place the optical component with four semi-reflective lenses in the same direction. Figure 3 Place the device into the device housing 5 in the direction shown and place it close to the positioning surface;

[0056] (4) Connect the optical fiber adapter 6 to the red light source;

[0057] (5) Grab a collimating lens 4 and adjust the position of the collimating lens 4 so that the four red light spots are within the reference circle;

[0058] (6) Adjust the position of the collimating lens 4 along the Z axis so that the longest optical path ( Figure 3 The radius of the red light spot at the bottom reaches the target value of 150um;

[0059] (7) Adjust the position of the collimating lens 4 along the X-axis and Y-axis directions so that the two sides ( Figure 3 The centers of the red light spots of the top and bottom two light spots coincide with the center of the photosensitive surface of PD1;

[0060] (8) Apply UV glue to collimating lens 4 and UV cure the glue to complete the coupling of collimating lens 4;

[0061] (9) Remove the optical assembly with four reflectors, install the next product, and continue coupling the collimating lens 4 of the next product;

[0062] (10) Put the product coupled with the collimating lens 4 into an oven to further cure the glue;

[0063] (11) The optical multiplexing component is passively attached to the device housing 5 and baked to fix;

[0064] (12) Fix the product to be coupled with the converging lens 3 on the machine platform, power on PD1, grab a converging lens 3 and move it to one of the channels, and adjust the position of the converging lens 3 so that the response degree of the corresponding channel PD1 reaches the maximum;

[0065] (13) Apply UV glue to the converging lens 3 and fix the position of the converging lens 3 by UV;

[0066] (14) Repeat steps 12 and 13 to complete the coupling of the converging lenses 3 of other channels;

[0067] (15) placing the product in an oven to further cure the glue;

[0068] (16) Product coupling is completed.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A coupling method for a multiplexed optical receiving submodule, characterized in that: The steps include: S1, fix the optical element in the device housing in a passive way, set a fiber optic adapter outside the device housing, and make a gold wire to complete the electrical connection; S2, fix the standard component with four PDs arranged in a line on the machine table; S3, fix the product to be coupled with collimated light on the machine table, and also install the optical component with four semi-reflective lenses into the device housing and position it; S4, connecting the optical fiber adapter to a red light source; S5, when adjusting the position of the collimating lens, the position and size of the four red light spots on the PD are observed on the computer screen through the CCD to determine the final position of the collimating lens, thereby completing the coupling of the collimating lens. The specific steps of adjusting the red light spot are as follows: On the screen, take the center of the photosensitive surface of the PD of the standard part as the center of the circle and draw four reference circles on the computer screen with R as the radius as the reference position. The value of R is between 150~300μm; Adjust the four red light spots projected onto the four PDs to be within the four circles; Adjust the position of the collimating lens along the Z-axis direction, select one of the channels, and adjust its spot size to a predetermined size; Adjust the position of the collimating lens along the X-axis and Y-axis directions so that the centers of the photosensitive surfaces of the first and last channels PD coincide with the centers of the corresponding red light spots.

2. A coupling method for a multiplexed optical receiving submodule as claimed in claim 1, characterized in that: The positioning method of the optical component is specifically as follows: a positioning surface is pre-arranged in the device housing, and when the optical component is placed in the device housing, the optical component is closely attached to the positioning surface, thereby completing the precise positioning of the optical component.

3. A coupling method for a multiplexed optical receiving submodule as claimed in claim 1, characterized in that: After the position of the collimating lens is determined, UV glue is applied to the collimating lens and the UV glue is cured to complete the coupling of the collimating lens.

4. The coupling method of a multiplexed optical receiving submodule as claimed in claim 1, characterized in that: After the coupling of the collimating lens is completed, the optical assembly is removed for coupling with the collimating lens of the next product.

5. The coupling method of a multiplexed optical receiving submodule as claimed in claim 1, characterized in that: Then, the optical multiplexing component is passively pasted into the device housing and fixed.

6. A coupling method for a multiplexed optical receiving submodule as claimed in claim 5, characterized in that: Fix the product to be coupled with the converging lens on the machine platform, power on the PD, grab a converging lens and move it to one of the channels, and adjust the position of the converging lens to maximize the responsiveness of the PD in the corresponding channel.

7. A coupling method for a multiplexed optical receiving submodule as claimed in claim 6, characterized in that: After the converging lens is adjusted, the converging lens is fixed.

8. A coupling method for a multiplexed optical receiving submodule as claimed in claim 7, characterized in that: Repeatedly grab another converging lens and move it to another channel, adjust the position of the converging lens to maximize the responsiveness of the corresponding channel PD, and fix the converging lens until all channel converging lenses are coupled.

9. A coupling method for a multiplexed optical receiving submodule as claimed in claim 8, characterized in that: After all optical components are coupled, place the product in an oven to further cure the glue.

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