Optical receiving end and 1.6t optical engine and coupling method

Abstract

This invention relates to an optical receiver coupling method. The method involves placing the 0° optical surface of a receiving fiber array against a cover plate of a multi-channel fiber array. The receiving fiber array is then moved downwards, reducing the gap between it and the multi-channel fiber array to 0.13 ± 0.01 mm, allowing the downward-sloping light output from the multi-channel fiber array to couple into the receiving fiber array. Movement is stopped when the optical power meter reading reaches its maximum. The gap is then widened. An array lens is placed within the gap, and the lens is moved until the optical power meter reading reaches its maximum. Transparent adhesive is then applied, and the lens is moved further until the optical power meter reading reaches its maximum again, at which point the adhesive is cured. A support block is fixed below the cover plate. A TIA chip is coupled onto the PCB board, and an array PD chip is mounted upside down on top of the TIA chip. In an active configuration, the multi-channel fiber array is coupled to the array PD chip via the array lens, and the support block is fixed to the PCB board. The advantages include superior performance and return loss, and high yield.

Description

Technical Field

[0001] This invention relates to the field of optical engine technology, specifically to an optical receiver, a 1.6T optical engine, and a coupling method. Background Technology

[0002] Traditional 1.6T optical engines consist of 8 transmitters and 8 receivers. The single-wavelength 200G array PD chip used in the 8 receivers has a very small photosensitive surface, typically only 8μm to 10μm. Furthermore, the array PD chip is usually mounted upside down on the TIA chip. To ensure yield, the optical receiver typically uses an array lens + multi-channel fiber array, as shown in the specific structure below. Figure 1 As shown, the optical receiver includes: a multi-channel fiber array, a pad, an array lens, an array PD chip, a TIA chip, and a PCB board. The cover plate of the multi-channel fiber array is glued to the PCB board. The pad is located below the total reflection surface of the multi-channel fiber array and is fixed to the PCB board. The tilt angle of the total reflection surface of the multi-channel fiber array is 42.5°±0.5°, preferably 42.5°. The TIA chip is fixed to the PCB board, and the array PD chip is upside down attached to the TIA chip. The array lens is located between the array PD chip and the total reflection surface of the multi-channel fiber array and is fixed to the pad. The array PD chip has a single-wavelength of 200G and is equipped with a lens. The multi-channel fiber array has four channels. The conventional method for this type of optical receiver is to align the array PD chip and the array lens using a passive patch method.

[0003] The shortcomings of this solution are as follows:

[0004] 1) It is required to use an expensive, high-precision pick-and-place machine to mount the array lenses, with a required accuracy of ±3μm and an angle of ±0.5°;

[0005] 2) Due to the thickness tolerance of materials such as array PD chip, TIA chip, pad, array lens, cover plate of multi-channel fiber array and substrate of multi-channel fiber array, there is generally a tolerance of ±10μm. Under extreme conditions, there is cumulative tolerance, that is, the distance between array PD chip, array lens and fiber core of multi-channel fiber array may deviate from the optimal coupling distance, as well as return loss (because the array lens and the lens of array PD chip are passive patches, so they cannot be adjusted in real time. In addition, there is an air gap between array lens and multi-channel fiber array, so there are two additional reflective surfaces), resulting in poor performance and low yield. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an optical receiver, a 1.6T optical engine and a coupling method to overcome the shortcomings of the prior art.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0008] An optical receiver coupling method includes the following steps:

[0009] S10. Place a multi-channel fiber array with a total reflection surface tilt angle of 42.5°±0.5° horizontally, and make the 0° optical surface end of a receiving fiber array closely attached to the cover plate of the multi-channel fiber array.

[0010] S20, each channel of the multi-channel fiber optic array is connected to an external light source, and each channel of the receiving fiber optic array is connected to an external optical power meter;

[0011] S30. Move the receiving fiber array downwards so that the gap between it and the multi-channel fiber array becomes 0.13mm ± 0.01mm, allowing the downward-sloping output light from the multi-channel fiber array to couple into the receiving fiber array. Stop moving when the optical power meter reading is at its maximum. The fiber core center in the multi-channel fiber array and the fiber core center in the receiving fiber array will be misaligned laterally by 0.05mm ± 0.01mm.

[0012] S40. Continue to move the receiving fiber array down, keeping other parameters unchanged, only increasing the gap;

[0013] S50. Place the array lens in the gap, move the array lens, and when the optical power meter reading is at its maximum, apply transparent adhesive and continue moving the array lens. When the optical power meter reading is at its maximum again, cure the adhesive to fix the array lens to the cover plate.

[0014] S60. A fixed support block is installed below the cover plate in a multi-channel fiber optic array;

[0015] S70, coupling the TIA chip on the PCB board, and upside down attaching the array PD chip with lens onto the TIA chip;

[0016] S80. In the active state, the multi-channel fiber optic array is coupled to the array PD chip through the array lens, and the support block is fixed to the PCB board.

[0017] The beneficial effects of this invention are: since the multi-channel fiber array and the array lens are actively coupled in the entire coupling process, and the array lens and the lens integrated in the array PD chip itself are also actively coupled, the performance and return loss can be optimized, resulting in high yield. Since the coupling is active, a high-precision pick-and-place machine is not required, thus reducing costs.

[0018] Based on the above technical solution, the present invention can be further improved as follows.

[0019] Furthermore, the multi-channel fiber array includes a substrate and a cover plate. The cover plate is attached to the underside of the substrate and fixes multiple optical fibers located in V-grooves on the substrate. The bare optical fibers are bonded to the substrate and the cover plate with soft adhesive. The end of the substrate has a total reflection surface with an inclination angle of 42.5°±0.5°, and the end of the cover plate has an inclined surface coplanar with the total reflection surface.

[0020] Furthermore, the end of the cover plate has a chamfer of C0.1mm.

[0021] The further beneficial effect of adopting the above is that the chamfer can prevent the glue from overflowing and contaminating the 42.5°±0.5° total reflective surface during dispensing.

[0022] Furthermore, the multi-channel fiber array has four channels.

[0023] Furthermore, the downward shift of the receiving fiber array in S30 reduces the gap between it and the multi-channel fiber array to 0.13 mm.

[0024] Furthermore, the fiber core center in the multi-channel fiber array of S30 is misaligned by 0.05mm with the fiber core center in the receiving fiber array.

[0025] Furthermore, the gap in S40 is changed to 0.85mm ± 0.01mm.

[0026] Furthermore, the S80 is detailed as follows:

[0027] Each channel of the multi-channel fiber optic array is connected to the output of an optical circulator. The input and isolation ends of each optical circulator are connected to a light source and an optical power meter, respectively. The multi-channel fiber optic array is then coupled to the array PD chip via an array lens. The optical power meter monitors the magnitude of the reflected return loss. By moving the relative positions of the multi-channel fiber optic array and the array PD chip, when both the array PD chip's responsivity and return loss are qualified, the support block below the multi-channel fiber optic array is bonded and fixed to the PCB board.

[0028] Based on the above technical solution, the present invention also provides an optical receiver, which is obtained by coupling using the above-described optical receiver coupling method.

[0029] The further beneficial effects of adopting the above are: optimal performance of the optical receiver and return loss, and high yield.

[0030] Based on the above technical solution, the present invention also provides a 1.6T optical engine, comprising: an optical receiver obtained by coupling using the optical receiver coupling method described above.

[0031] The further beneficial effects of adopting the above are: effectively improving the performance of the 1.6T optical engine, achieving high yield, and minimizing return loss. Attached Figure Description

[0032] Figure 1 This is a structural diagram of an optical receiver in the prior art;

[0033] Figure 2 This is a structural diagram of the optical receiver in this invention;

[0034] Figure 3 This is a coupling state diagram in S10 of the present invention;

[0035] Figure 4 This is a coupling state diagram in S30 of the present invention;

[0036] Figure 5 This is a coupling state diagram in S40 of the present invention;

[0037] Figure 6 This is a coupling state diagram in S50 of the present invention;

[0038] Figure 7 This is a coupling state diagram in S60 of the present invention;

[0039] Figure 8 This is a main view of the coupling state in S80 of the present invention;

[0040] Figure 9 This is a top view of the coupling state portion in S80 of the present invention;

[0041] Figure 10 This is a graph showing the relationship between the offset and coupling efficiency of the optical fiber array and the multi-channel optical fiber array in this invention.

[0042] The attached diagram lists the components represented by each number as follows:

[0043] 1. Multi-channel fiber optic array, 110. Cover plate, 111. Chamfer, 120. Substrate, 130. Fiber optic cable, 140. Soft adhesive, 2. Array lens, 3. Support block, 4. TIA chip, 5. Array PD chip, 6. PCB board, 7. Light receiving fiber optic array, 8. Light source, 9. Optical power meter, 10. Optical circulator. Detailed Implementation

[0044] 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.

[0045] Example 1

[0046] like Figures 2-9 As shown, an optical receiver coupling method includes the following steps:

[0047] S10. A multi-channel fiber array 1 is placed horizontally, and a light-receiving fiber array 7 is placed vertically below the multi-channel fiber array 1. The tilt angle of the total reflection surface of the multi-channel fiber array 1 is 42.5°±0.5°. The total reflection light of the 42.5°±0.5° total reflection surface has the characteristic of tilting downward. The optical surface end of the light-receiving fiber array 7 is the 0° surface. Then, the 0° optical surface end of the light-receiving fiber array 7 is placed close to the cover plate 110 of the multi-channel fiber array 1. That is, the gap between the 0° optical surface end of the light-receiving fiber array 7 and the cover plate 110 of the multi-channel fiber array 1 is 0mm.

[0048] S20. Each channel of the multi-channel fiber array 1 is connected to an external light source 8, and each channel of the receiving fiber array 7 is connected to an external optical power meter 9. For example, if the multi-channel fiber array 1 has four channels, then four external light sources 8 are connected, and the receiving fiber array 7 also has four channels and four external optical power meters 9 are connected.

[0049] S30. Move the receiving fiber array 7 downwards, reducing the gap between the receiving fiber array 7 and the multi-channel fiber array 1 to 0.13mm ± 0.01mm. Simultaneously, couple the receiving fiber array 7 by moving it, that is, couple the downward-sloping light output from the multi-channel fiber array 1 into the receiving fiber array 7. Specifically, this can be understood as: the light from the fiber core in the multi-channel fiber array 1 passes through the cover plate 110 and is coupled downwards into the fiber core in the receiving fiber array 7. The optical power meter 9 will begin to register a reading. When the optical power meter 9 reaches its maximum reading, stop moving the receiving fiber array 7. At this point, the fiber core in the receiving fiber array 7 and the fiber core in the multi-channel fiber array 1 are coupled... The optical paths are aligned, and the center of the fiber core in the multi-channel fiber array 1 and the center of the fiber core in the receiving fiber array 7 will have a lateral misalignment of 0.05mm ± 0.01mm. Taking the figure as an example, this misalignment refers to a misalignment in the left-right direction, not the front-back direction. The misalignment of 0.05mm ± 0.01mm is the optimal misalignment point required for the subsequent coupling of the array lens 2. This step cannot be omitted because: only when the gap is 0.13mm ± 0.01mm will the optical power meter 9 connected to the receiving fiber array 7 have light display. Only when there is light display can subsequent coupling and alignment be performed. If the receiving fiber array 7 cannot receive light, the subsequent steps cannot be performed.

[0050] Figure 10This diagram illustrates the relationship between the offset and coupling efficiency of the receiving fiber array and the multi-channel fiber array in this invention. The horizontal axis represents the offset of the receiving fiber array and the multi-channel fiber array (in mm), and the vertical axis represents the coupling efficiency. Optical simulations show that the coupling efficiency is optimal when the gap between the receiving fiber array and the multi-channel fiber array is 0.13 mm and the offset is 0.05 mm. This explains the principle of active coupling: the offset of the receiving fiber array and the multi-channel fiber array can be precisely controlled (the accuracy can reach ±0.3 μm, which is an order of magnitude higher than that of passive patches).

[0051] S40. Continue to move the receiving fiber array 7 down, keeping other parameters unchanged. Other parameters refer to: the misalignment distance remains unchanged and the front, back, left, and right positions of the fiber core in the receiving fiber array 7 remain unchanged, only the gap is increased, and this gap is sufficient to allow the array lens 2 to be placed later.

[0052] S50. Place array lens 2 in the gap, and then move array lens 2. Moving array lens 2 means changing the front, back, left, and right positions of array lens 2. When the optical power meter 9 reads the maximum, apply light-transmitting adhesive between array lens 2 and multi-channel fiber array 1, and continue to move array lens 2. Similarly, change the front, back, left, and right positions of array lens 2. When the optical power meter 9 reads the maximum again, cure the adhesive. Curing adhesive can be achieved by irradiating with UV light to fix array lens 2 to cover plate 110. At this time, the center line of array lens 2 is actually misaligned with the fiber core center in multi-channel fiber array 1. The coupling position of array lens 2 is close to the optimal coupling position of subsequent array PD chip 5, with an error of ±0.3μm, which is an order of magnitude higher than that of passive patch.

[0053] S60. A support block 3 is fixed below the cover plate 110 in the multi-channel fiber array 1. The support block 3 can be made of glass and can be fixed by adhesive bonding.

[0054] S70, TIA chip 4 is coupled on PCB board 6, and array PD chip 5 with lens is inverted and attached to TIA chip 4. Array PD chip 5 is also single-wavelength 200G, which is consistent with the existing technology.

[0055] S80. In the active state, the multi-channel fiber array 1 is coupled to the array PD chip 5 through the array lens 2, and the support block 3 is fixed to the PCB board 6.

[0056] Example 2

[0057] like Figure 2 As shown, this embodiment is a further improvement on embodiment 1, as detailed below:

[0058] The multi-channel fiber array 1 includes a substrate 120 and a cover plate 110. The cover plate 110 is attached to the underside of the substrate 120 and fixes multiple optical fibers 130 located in V-grooves on the substrate 120. The bare optical fibers of the optical fibers 130 are bonded to the substrate 120 and the cover plate 110 with soft adhesive 140. The end of the substrate 120 has a total reflection surface with an inclination angle of 42.5°±0.5°, and the end of the cover plate 110 has an inclined surface coplanar with the total reflection surface.

[0059] Furthermore, the end of the cover plate 110 has a chamfer 111 with a diameter of C0.1mm. This chamfer 111 can prevent the glue from overflowing and contaminating the 42.5°±0.5° total reflective surface during dispensing.

[0060] In this embodiment, the multi-channel fiber array 1 has four channels, which is consistent with the existing technology.

[0061] Example 3

[0062] like Figure 4 As shown, this embodiment is a further improvement on embodiment 1 or 2, as detailed below:

[0063] In S30, the downward movement of the receiving fiber array 7 reduces the gap between it and the multi-channel fiber array 1 to 0.13 mm. At this time, the fiber core center in the multi-channel fiber array 1 and the fiber core center in the receiving fiber array 7 are misaligned by 0.05 mm in the lateral direction.

[0064] Example 4

[0065] like Figure 5 As shown, this embodiment is a further improvement on embodiment 1, 2, or 3, as detailed below:

[0066] The gap in S40 is changed to 0.85mm±0.01mm. As a preferred option, the gap is changed to 0.85mm. When the gap is increased from 0.13mm±0.01mm to 0.85mm±0.01mm, the light receiving fiber array 7 is without light. Only by coupling an array lens 2 can the light receiving fiber array 7 be made to have light again.

[0067] Example 5

[0068] like Figure 8 , Figure 9 As shown, this embodiment is a further improvement on embodiment 1, 2, 3, or 4, as detailed below:

[0069] The S80 is detailed below:

[0070] Each channel of the multi-channel fiber array 1 is connected to the output of an optical circulator 10. The input and isolation ends of each optical circulator 10 are connected to a light source 8 and an optical power meter 9, respectively. The multi-channel fiber array 1 is then coupled to the array PD chip 5 through the array lens 2. The optical power meter 9 monitors the magnitude of the reflected return loss. By moving the relative positions of the multi-channel fiber array 1 and the array PD chip 5, when the responsivity and return loss of the array PD chip 5 are both qualified, the support block 3 below the multi-channel fiber array 1 is glued and fixed to the PCB board 6.

[0071] Example 6

[0072] like Figure 2 As shown, an optical receiver is obtained by coupling using the optical receiver coupling method of any one of the embodiments 1 to 5.

[0073] Example 7

[0074] like Figure 2 As shown, a 1.6T optical engine includes an optical receiver coupled using the optical receiver coupling method of any one of embodiments 1 to 5.

[0075] 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 coupling an optical receiver, characterized in that, Includes the following steps: S10. A multi-channel fiber array with a total reflection surface tilt angle of 42.5°±0.5° is placed horizontally. The multi-channel fiber array includes a substrate and a cover plate. The end of the substrate has a total reflection surface with a tilt angle of 42.5°±0.5°, and the 0° light surface end of a light-receiving fiber array is vertically attached to the cover plate of the multi-channel fiber array. S20, each channel of the multi-channel fiber optic array is connected to an external light source, and each channel of the receiving fiber optic array is connected to an external optical power meter; S30. Move the receiving fiber array downwards so that the gap between it and the multi-channel fiber array becomes 0.13mm ± 0.01mm, allowing the downward-sloping output light from the multi-channel fiber array to couple into the receiving fiber array. Stop moving when the optical power meter reading is at its maximum. The fiber core center in the multi-channel fiber array and the fiber core center in the receiving fiber array will be misaligned laterally by 0.05mm ± 0.01mm. S40. Continue to move the receiving fiber array down, keeping other parameters unchanged, only increasing the gap; S50. Place the array lens in the gap, move the array lens, and when the optical power meter reading is at its maximum, apply transparent adhesive and continue moving the array lens. When the optical power meter reading is at its maximum again, cure the adhesive to fix the array lens to the cover plate. S60. A fixed support block is installed below the cover plate in a multi-channel fiber optic array. S70, coupling the TIA chip on the PCB board, and upside down attaching the array PD chip with lens onto the TIA chip; S80. In the active state, the multi-channel fiber optic array is coupled to the array PD chip through the array lens, and the support block is fixed to the PCB board.

2. The optical receiver coupling method according to claim 1, characterized in that, The multi-channel fiber array includes a substrate and a cover plate. The cover plate is attached to the underside of the substrate and fixes multiple optical fibers located in V-grooves on the substrate. The bare optical fibers are bonded to the substrate and the cover plate with soft adhesive. The end of the substrate has a total reflection surface with an inclination angle of 42.5°±0.5°, and the end of the cover plate has an inclined surface coplanar with the total reflection surface.

3. The optical receiver coupling method according to claim 2, characterized in that, The end of the cover plate has a chamfer of C0.1mm.

4. A coupling method for an optical receiver according to any one of claims 1 to 3, characterized in that, The multi-channel fiber optic array has four channels.

5. The optical receiver coupling method according to claim 1, characterized in that, In the S30, the downward shift of the receiving fiber array reduces the gap between it and the multi-channel fiber array to 0.13 mm.

6. The optical receiver coupling method according to claim 5, characterized in that, In the S30, the fiber core center in the multi-channel fiber array and the fiber core center in the receiving fiber array are misaligned by 0.05 mm laterally.

7. The optical receiver coupling method according to claim 1, characterized in that, The gap in S40 becomes 0.85mm±0.01mm.

8. The optical receiver coupling method according to claim 1, characterized in that, The S80 is detailed below: Each channel of the multi-channel fiber optic array is connected to the output of an optical circulator. The input and isolation ends of each optical circulator are connected to a light source and an optical power meter, respectively. The multi-channel fiber optic array is then coupled to the array PD chip via an array lens. The optical power meter monitors the magnitude of the reflected return loss. By moving the relative positions of the multi-channel fiber optic array and the array PD chip, when both the array PD chip's responsivity and return loss are qualified, the support block below the multi-channel fiber optic array is bonded and fixed to the PCB board.

9. An optical receiver, characterized in that, The optical receiver coupling method described in any one of claims 1 to 8 is used.

10. A 1.6T light engine, characterized in that, include: An optical receiver obtained by coupling using the optical receiver coupling method as described in any one of claims 1 to 8.

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