A receiver optical path and an 800G 2×FR4 silicon photonics engine

Abstract

The utility model relates to a kind of receiving end optical path, four optical filters and a corner prism are sequentially fixed on the side surface of Z-block adjacent lens array;Two first converging lenses have at corresponding each optical filter on lens array, two first collimating lenses have at corresponding corner prism on lens array, second RX fiber has at corresponding each first converging lens in first RX fiber array, first RX fiber has at corresponding each first collimating lens in first RX fiber array;The tail fiber of second RX fiber in odd channel enters one second RX fiber array, the tail fiber of second RX fiber in even channel enters another second RX fiber array.A kind of 800G 2×FR4 silicon light light engine, receiving end optical path, optical transmitting end and DSP chip are fixed on the front of PCB board.The beneficial effect is that coupling difficulty is greatly reduced, low in cost, and PD array can be selected according to demand.

Description

Technical Field

[0001] This utility model relates to the field of optical engine technology, specifically to a receiver optical path and an 800G 2×FR4 silicon photonics engine. Background Technology

[0002] The structural diagram of a traditional 800G 2×FR4 silicon photonics engine is shown below. Figure 1 , Figure 2 , Figure 3 As shown, it includes: a PCB board and a light emitter, two light receivers, and a DSP chip fixed on the front side of the PCB board. The light emitter and the two light receivers are arranged side-by-side along the width of the PCB board. The light receivers include: a substrate and an RX fiber array, a Z-block assembly, and a 45° reflecting prism sequentially fixed on the substrate. A collimating lens is coupled between the RX fiber array and the light inlet of the Z-block assembly, and the collimating lens is bonded to the end face of the RX fiber array. A four-channel array lens is coupled between the light outlet of the Z-block assembly and the 45° reflecting prism, and the four-channel array lens is bonded to the 45° reflecting prism. On the end face of the reflecting prism, a PD array fixed to the PCB board is coupled below the reflecting surface of the 45° reflecting prism. The PD array is electrically connected to the TIA chip. The optical transmitter includes a silicon photonics chip, a TX fiber array, and four laser chips. The four laser chips are arranged in a row with different wavelengths. Each laser chip is coupled to one input waveguide of the silicon photonics chip after passing through a second collimating lens, an optical isolator, and a second converging lens. The two output waveguides of the silicon photonics chip are coupled to two TX fibers in the TX fiber array. The RX fiber in the optical receiver and the TX fiber in the optical transmitter are each connected to an LC adapter.

[0003] With traditional processes, Z-blocks in current Z-block modules cannot achieve a pitch of 0.25mm; the minimum current pitch is 0.5mm. Z-blocks with this pitch are relatively expensive. However, when the Z-block pitch is greater than or equal to 0.75mm, the cost is normal. Therefore, Z-blocks with a pitch of 0.75mm are commonly used. Since the 800G 2×FR4 silicon photonics engine has two light receivers, it has two Z-block modules. The disadvantage is that the Z-block modules are large and occupy PCB layout space. Using two Z-block modules, and each Z-block module needs to be coupled with a collimating lens and a converging lens, for a total of four couplings, and also requires the use of expensive 45° reflecting prisms, all of which result in a higher overall cost. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a receiver optical path and an 800G 2×FR4 silicon photonics engine to overcome the shortcomings of the prior art.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: An optical path for a receiver includes: a Z-block, a lens array, and a first RX fiber array arranged side by side. Four filters and a corner prism are fixed sequentially along the length of the side of the Z-block adjacent to the lens array. The side of the Z-block away from the lens array is a light-reflecting surface. The lens array has two first converging lenses coupled to each filter, and two first collimating lenses coupled to each corner prism. The first RX fiber array contains second RX fibers coupled to each first converging lens and each first RX fiber coupled to each first collimating lens. Pigtails of the second RX fibers in odd-numbered channels of the first RX fiber array enter one second RX fiber array, and pigtails of the second RX fibers in even-numbered channels of the first RX fiber array enter another second RX fiber array.

[0006] The beneficial effects of this utility model are: This solution uses a Z-block to address the RX wavelength division problem, and only requires coupling a single integrated lens array (meaning the converging and collimating lenses are designed as a single unit), significantly reducing coupling difficulty and cost. It also allows two light paths to share a single filter, further reducing costs. Because a corner prism is used to convert horizontal light into tilted light and couple it into the Z-block, the light entering and exiting the Z-block can be handled by a single first RX fiber array, reducing costs. Only an RX fiber array with a suitable channel spacing needs to be selected to match a PD array with a corresponding spacing; for example, selecting… A second RX fiber array with a 250μm pitch corresponds to a PD array with a 250μm pitch; a second RX fiber array with a 500μm pitch corresponds to a PD array with a 500μm pitch; and a second RX fiber array with a 750μm pitch corresponds to a PD array with a 750μm pitch. This provides greater overall flexibility, and allows for the selection of PD arrays with appropriate cost based on requirements. For example, a low-cost PD array with a 250μm pitch, using only one Z-block, can effectively reduce the space occupied on the PCB board, which is beneficial for PCB layout.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the center-to-center distance between two adjacent filters on the side of the Z-block is 1 mm.

[0009] The further beneficial effects of adopting the above are: the spacing is a conventional spacing, the two light paths share a single filter, and the cost is reduced by half.

[0010] Furthermore, the center-to-center distance between two first converging lenses coupled to the same filter is 250 μm, and the center-to-center distance between two adjacent first collimating lenses is 250 μm.

[0011] Furthermore, each second RX fiber array is coupled to a PD array, and each PD array is electrically connected to a TIA chip.

[0012] Furthermore, the center-to-center spacing between two adjacent optical channels in the PD array is 250μm, 500μm, or 750μm.

[0013] Furthermore, the Z-block, lens array, and first RX fiber array are fixed on the same substrate.

[0014] Based on the above technical solution, this utility model also provides an 800G 2×FR4 silicon photonics engine, including: a PCB board, a light emitting end, a DSP chip, and a receiving end optical path, wherein the receiving end optical path, the light emitting end, and the DSP chip are fixed on the front side of the PCB board.

[0015] The further beneficial effects of adopting the above are: more convenient PCB layout, very low requirements for fiber length tolerance during packaging, and low cost.

[0016] Furthermore, the optical transmitter includes a silicon photonics chip, a TX fiber array, and four laser chips. The four laser chips are arranged in a row with different wavelengths. Each laser chip is coupled to one input waveguide of the silicon photonics chip after passing through a second collimating lens, an optical isolator, and a second converging lens. The two output waveguides of the silicon photonics chip are coupled to two TX fibers in the TX fiber array.

[0017] Furthermore, the two TX fibers of the TX fiber array are connected to two LC adapters respectively.

[0018] Furthermore, the two first RX fibers of the first RX fiber array are respectively connected to two LC adapters. Attached Figure Description

[0019] Figure 1 A top view of an existing 800G 2×FR4 silicon photonics engine; Figure 2 This is a top view of an optical receiver in the prior art; Figure 3 This is a front view of an optical receiver in the prior art; Figure 4This is a top view of the optical path structure of the receiving end in this utility model; Figure 5 This is a front view of the optical path structure of the receiving end in this utility model; Figure 6 This is a top view of the 800G 2×FR4 silicon photonics engine in this utility model; Figure 7 This is a top view of the light emitting end in this utility model.

[0020] The attached diagram lists the components represented by each number as follows: 1. Receiver optical path, 110 Z-block, 120 Lens array, 121 First converging lens, 122 First collimating lens, 130 First RX fiber array, 131 Second RX fiber, 132 First RX fiber, 140 Filter, 150 Corner prism, 160 Second RX fiber array, 170 PD array, 180 TIA chip, 190 Substrate, 2. PCB board, 3. Optical transmitter, 310 Silicon photonics chip, 320 TX fiber array, 321 TX fiber, 330 Laser chip, 340 Second collimating lens, 350 Optical isolator, 360 Second converging lens, 4. DSP chip, 5. LC adapter. Detailed Implementation

[0021] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model. Example 1

[0022] like Figure 4 , Figure 5 , Figure 6 As shown, a receiver optical path includes: a Z-block 110, a lens array 120, and a first RX fiber array 130. The Z-block 110, the lens array 120, and the first RX fiber array 130 are arranged side by side in sequence. Four filters 140 and a corner prism 150 are fixed in sequence on the side of the Z-block 110 adjacent to the lens array 120. The four filters 140 and the corner prism 150 are arranged in sequence along the length of the Z-block 110, while the side of the Z-block 110 away from the lens array 120 is a light reflecting surface. The lens array 120 has two first converging lenses 121 coupled to each filter 140, i.e., the number of first converging lenses 121 is eight. The lens array 120 also has two first collimating lenses 122 coupled to each corner prism 150, i.e., the number of first collimating lenses 122 is two. The first RX fiber array 130 has two second RX fibers 131 coupled to each first converging lens 121, i.e., the number of second RX fibers 131 is eight. The first RX fiber array 130 also has two first RX fibers 132 coupled to each first collimating lens 122, i.e., the number of first RX fibers 132 is two. The pigtails of the second RX fiber 131 in the odd-numbered channels of the first RX fiber array 130 enter a second RX fiber array 160, while the pigtails of the second RX fiber 131 in the even-numbered channels of the first RX fiber array 130 enter another second RX fiber array 160. That is, there are two second RX fiber arrays 160. The pigtails of the second RX fiber 131 entering the second RX fiber array 160 can be understood as the pigtails of the second RX fiber 131 entering the V-groove of the second RX fiber array 160 after the bare fiber is stripped.

[0023] Each external RX light enters a first RX fiber 132, and is then coupled from the first RX fiber 132 to the first collimating lens 122, and then from the first collimating lens 122 to the corner prism 150. The corner prism 150 converts the horizontal light into tilted light, for example, tilted at 13.5°, and thus couples it into the Z-block 110, and splits it into four light beams of different wavelengths. Then, they are emitted from four filters 140 respectively, and the four light beams of different wavelengths are coupled into the second RX fiber 131 through the first converging lens 121 respectively. This solution uses a Z-block 110 to address the RX wavelength division problem, and only requires coupling with an integrated lens array 120 (referring to the convergent and collimating lenses being designed as a single unit). This significantly reduces coupling difficulty and cost. It also allows two light paths to share a single filter, further reducing costs. Because a corner prism 150 converts horizontal light into tilted light and couples it into the Z-block 110, the light entering and exiting the Z-block 110 can be handled by a single first RX fiber array 130, further reducing costs. Only a second RX fiber array 160 with a suitable channel spacing needs to be selected to match the corresponding PD array. For example, if you choose a second RX fiber array 160 with a 250μm pitch, then it corresponds to a PD array 170 with a 250μm pitch; if you choose a second RX fiber array 160 with a 500μm pitch, then it corresponds to a PD array 170 with a 500μm pitch; if you choose a second RX fiber array 160 with a 750μm pitch, then it corresponds to a PD array 170 with a 750μm pitch. This provides better overall flexibility, and you can also choose a lower-cost PD array 170 according to your needs. Using only one Z-block 110 can effectively reduce the space occupied on PCB board 2, which is beneficial for PCB board 2 layout. Example 2

[0024] like Figure 4 As shown, this embodiment is a further improvement on embodiment 1, as detailed below: The center-to-center distance between two adjacent filters 140 on the side of the Z-block110 is 1mm, which is a standard distance. Both light paths share one filter, reducing costs by half. With traditional processes, the Z-block110 cannot currently achieve a distance of 0.25mm; the minimum distance is currently 0.5mm. The cost of the Z-block110 with this distance is relatively high, while the cost is normal when the distance of the Z-block110 is greater than or equal to 0.75mm.

[0025] Furthermore, the center-to-center distance between the two first converging lenses 121 coupled to the same filter 140 is 250 μm. Assuming that the eight second RX fibers 131 in the first RX fiber array 130 are, in order, the first RX fiber, the second RX fiber, the third RX fiber, the fourth RX fiber, the fifth RX fiber, the sixth RX fiber, the seventh RX fiber, and the eighth RX fiber, then the center-to-center distance between the first RX fiber and the second RX fiber is 250 μm, the center-to-center distance between the third RX fiber and the fourth RX fiber is 250 μm, the center-to-center distance between the fifth RX fiber and the sixth RX fiber is 250 μm, the center-to-center distance between the seventh RX fiber and the eighth RX fiber is 250 μm, the center-to-center distance between the RX fibers of the odd-numbered channels is 1 mm, and the center-to-center distance between the RX fibers of the even-numbered channels is 1 mm; the center-to-center distance between two adjacent first collimating lenses 122 is 250 μm. Example 3

[0026] like Figure 5 , Figure 6 As shown, this embodiment is a further improvement on embodiment 1 or 2, as detailed below: Each second RX fiber array 160 is coupled to a PD array 170. The second RX fiber array 160 can be a conventional 42.5° fiber array. Each PD array 170 is electrically connected to a TIA chip 180, thus having two PD arrays 170 and two TIA chips 180.

[0027] Furthermore, the center-to-center spacing between two adjacent optical channels in the PD array 170 is 250μm, 500μm, or 750μm. Assuming a second RX fiber array 160 with a spacing of 250μm is selected, then a PD array 170 with a spacing of 250μm will be matched accordingly; assuming a second RX fiber array 160 with a spacing of 500μm is selected, then a PD array 170 with a spacing of 500μm will be matched accordingly; assuming a second RX fiber array 160 with a spacing of 750μm is selected, then a PD array 170 with a spacing of 750μm will be matched accordingly; if a PD array 170 with a spacing of 250μm is selected, then the cost is the lowest. Example 4

[0028] like Figure 4 , Figure 6 As shown, this embodiment is a further improvement on embodiment 1, 2, or 3, as detailed below: Z-block 110 is fixed on substrate 190, lens array 120 is fixed on substrate 190, and first RX fiber array 130 is fixed on substrate 190. Example 5

[0029] like Figure 6 , Figure 7 As shown, an 800G 2×FR4 silicon photonics engine includes: a PCB board 2, an optical transmitter 3, a DSP chip 4, and a receiver optical path 1 as in any of embodiments 1 to 4. The receiver optical path 1, the optical transmitter 3, and the DSP chip 4 are fixed on the front side of the PCB board 2. In the receiver optical path 1, the substrate 190 is fixed on the front side of the PCB board 2, the second RX fiber array 160 is fixed on the front side of the PCB board 2, and the PD array 170 and the TIA chip 180 are also fixed on the front side of the PCB board 2.

[0030] In actual production, two second RX fiber arrays 160 are first coupled and fixed. Then, the lengths of the second RX fiber 131 and the first RX fiber 132 in the first RX fiber array 130 are freely arranged. Then, glue is applied to fix the substrate 190 on the PCB board 2. In addition, the first RX fiber 132 is bent 90° and then encapsulated in the housing. Therefore, the fiber length tolerance requirement is very low, which further reduces the cost.

[0031] Furthermore, the optical transmitter 3 includes a silicon photonics chip 310, a TX fiber array 320, and four laser chips 330. The four laser chips 330 are arranged in a row with different wavelengths. Each laser chip 330 is coupled to one of the input waveguides of the silicon photonics chip 310 after passing through a second collimating lens 340, an optical isolator 350, and a second converging lens 360 in sequence. Thus, it has four second collimating lenses 340, four optical isolators 350, and four second converging lenses 360. The two output waveguides of the silicon photonics chip 310 are coupled to two TX fibers 321 in the TX fiber array 320. The second collimating lenses 340, optical isolators 350, second converging lenses 360, and silicon photonics chip 310 are fixed on the front side of the PCB board 2, while the laser chips 330 are fixed on the front side of the PCB board 2 by a ceramic heat sink.

[0032] The two TX fibers 321 of the TX fiber array 320 are connected to the two LC adapters 5 respectively, and the two first RX fibers 132 of the first RX fiber array 130 are connected to the two LC adapters 5 respectively, thus providing four LC adapters 5.

[0033] 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 receiving optical path, characterized in that, include: A Z-block (110), a lens array (120), and a first RX fiber array (130) are arranged side by side. Four filters (140) and a corner prism (150) are fixed sequentially along the length of the side of the Z-block (110) adjacent to the lens array (120). The side of the Z-block (110) away from the lens array (120) is a light-reflecting surface. The lens array (120) has two first converging lenses (121) coupled to each filter (140), and two first collimating lenses (121) coupled to each corner prism (150). A straight lens (122) is provided. The first RX fiber array (130) has a second RX fiber (131) coupled to each of the first converging lenses (121). The first RX fiber array (130) has a first RX fiber (132) coupled to each of the first collimating lenses (122). The pigtail of the second RX fiber (131) in the odd-numbered channel of the first RX fiber array (130) enters a second RX fiber array (160). The pigtail of the second RX fiber (131) in the even-numbered channel of the first RX fiber array (130) enters another second RX fiber array (160).

2. The receiving optical path according to claim 1, characterized in that, The center-to-center distance between two adjacent filters (140) on the side of the Z-block (110) is 1 mm.

3. A receiving optical path according to claim 1 or 2, characterized in that, The center-to-center distance between two first converging lenses (121) coupled to the same filter (140) is 250 μm, and the center-to-center distance between two adjacent first collimating lenses (122) is 250 μm.

4. The receiving optical path according to claim 1, characterized in that, Each second RX fiber array (160) is coupled to a PD array (170), and each PD array (170) is electrically connected to a TIA chip (180).

5. The receiving optical path according to claim 4, characterized in that, The center-to-center distance between two adjacent optical channels in the PD array (170) is 250μm, 500μm or 750μm.

6. The receiving optical path according to claim 1, characterized in that, The Z-block (110), lens array (120) and first RX fiber array (130) are fixed on the same substrate (190).

7. An 800G 2×FR4 silicon photonics engine, characterized in that, include: The PCB board (2), the light transmitter (3), the DSP chip (4) and the receiver optical path (1) as described in any one of claims 1 to 6 are fixed on the front side of the PCB board (2).

8. An 800G 2×FR4 silicon photonics engine according to claim 7, characterized in that, The optical transmitter (3) includes a silicon photonic chip (310), a TX fiber array (320), and four laser chips (330). The four laser chips (330) are arranged in a row and have different wavelengths. Each laser chip (330) is coupled to one of the input waveguides of the silicon photonic chip (310) after passing through a second collimating lens (340), an optical isolator (350), and a second converging lens (360). The two output waveguides of the silicon photonic chip (310) are coupled to two TX fibers (321) in the TX fiber array (320).

9. An 800G 2×FR4 silicon photonics engine according to claim 8, characterized in that, The two TX fibers (321) of the TX fiber array (320) are connected to two LC adapters (5) respectively.

10. An 800G 2×FR4 silicon photonics engine according to claim 7, characterized in that, The two first RX fibers (132) of the first RX fiber array (130) are respectively connected to two LC adapters (5).

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