Optical transceiver module and packaging method thereof

Abstract

The present invention relates to an optical transceiver module and a packaging method thereof, wherein the optical transceiver module comprises a printed circuit board, the printed circuit board is provided with a through slot, an iron sheet is fixedly arranged below the through slot, a ceramic substrate is fixedly arranged on the upper surface of the iron sheet, a vertical cavity surface emitting laser, a surface receiving detector, a laser driver chip, a transimpedance amplifier chip and an optical fiber array are mounted on the surface of the ceramic substrate, and the ceramic substrate and various components mounted on the surface are covered and packaged by epoxy resin black glue. The optical transceiver module of the present invention has many advantages such as low cost, high reliability, good heat dissipation performance, compact structure, strong scalability and the like.

Description

Technical Field

[0001] The present invention relates to an optical transceiver module and a packaging method thereof, in particular to an integrated optical transceiver module, belonging to the technical field of optical fiber communication. Background Art

[0002] As one of the solutions for high-speed and large-capacity interconnection transmission, optical transceiver modules are widely used in wireless base stations, Ethernet networking, data centers, and the emerging 5G transmission architecture in recent years. Its technology and cost have considerable advantages over the traditional use of copper wiring for signal transmission. Cables based on traditional copper wiring have disadvantages such as bulkiness, large bending radius, high power consumption, short transmission distance, and low rate. Optical transceiver modules have many advantages in using light to transmit signals, such as lower transmission power on the link, only one-fourth the weight of direct copper cables, about half the volume of copper cables, smaller bending radius, more convenient wiring in the computer room, better air flow and heat dissipation, and longer transmission distance.

[0003] One of the core parts of the optical transceiver module is the packaging of the optical device. At present, many optical transceiver modules on the market use TOSA and ROSA discrete packaging, which occupies a large amount of limited design space in the module, compresses the flexibility of printed circuit board PCB design, complicates the heat dissipation design, and increases the complexity of the entire module assembly.

[0004] Therefore, in order to solve the above technical problems, it is necessary to provide an innovative optical transceiver module and method thereof to overcome the above defects in the prior art. Summary of the invention

[0005] To solve the above problems, the object of the present invention is to provide an optical module and a method thereof which has low cost, high reliability, good heat dissipation, compact structure and strong scalability.

[0006] To achieve the above object, the present invention provides a technical solution:

[0007] An optical transceiver module comprises at least one optical fiber array, at least one ceramic substrate, at least one iron sheet, at least one piece of heat dissipation silicone grease, at least one vertical cavity surface emitting laser, at least one surface receiving detector, at least one laser driver chip, at least one transimpedance amplifier chip, and at least one printed circuit board, wherein the printed circuit board is provided with a through slot, the iron sheet is fixedly arranged on the lower surface of the printed circuit board, the iron sheet is located below the through slot, and the heat dissipation silicone grease is adhered to the back of the iron sheet;

[0008] The ceramic substrate is fixedly arranged on the upper surface of the iron sheet, the vertical cavity surface emitting laser, the surface receiving detector, the laser driver chip and the transimpedance amplifier chip are respectively mounted on the surface of the ceramic substrate, the optical fiber array is bonded in parallel to the surface of the ceramic substrate, and the ceramic substrate and various components mounted on the surface are covered and packaged by epoxy resin black glue;

[0009] The vertical cavity surface emitting laser and the surface receiving light detector are linked to the optical fiber array through a refractive index matching glue to realize signal transmission. The vertical cavity surface emitting laser is electrically connected to the laser driving chip, the surface receiving detector is electrically connected to the transimpedance amplifier chip, and the laser driving chip and the transimpedance amplifier chip are electrically connected to the printed circuit board respectively.

[0010] Furthermore, the iron sheet is adhered to the printed circuit board just below the through slot by means of ultraviolet curing adhesive.

[0011] Furthermore, the ceramic substrate is plated with a gold layer and an alignment mark, and the laser driver chip and the transimpedance amplifier chip are mounted on the gold layer, which is convenient for binding and wire bonding of the laser driver chip and the transimpedance amplifier chip; the vertical cavity surface emitting laser and the surface receiving detector are mounted on the alignment mark, which is convenient for precise positioning of the vertical cavity surface emitting laser and the surface receiving detector.

[0012] Furthermore, the vertical cavity surface emitting laser, the surface receiving detector, the laser driving chip and the transimpedance amplifier chip are respectively mounted on the surface of the ceramic substrate through silver paste.

[0013] Furthermore, the ceramic substrate is adhered to the iron sheet by silver paste, and the silver paste can enhance the heat conduction between the ceramic substrate and the iron sheet.

[0014] Furthermore, the optical fiber array includes a plurality of single-mode optical fibers arranged in parallel, the end faces of the optical fibers used for coupling are at an angle of 45°, and the end faces are coated with a metal film to enhance reflection.

[0015] Furthermore, a microcontroller chip is also provided on the printed circuit board, and the microcontroller chip is electrically connected to the pads on the printed circuit board through wiring.

[0016] Furthermore, the optical transceiver module also includes a metal shell, the printed circuit board is placed in the metal shell, and the heat dissipation silicone grease attached to the back of the iron sheet is in contact with the metal shell to enhance the overall heat dissipation of the module.

[0017] The present invention also provides a technical solution:

[0018] The packaging method of the optical transceiver module comprises the following steps:

[0019] (1) The iron sheet is adhered to the bottom of the through slot of the printed circuit board by means of UV curing adhesive and fixed by UV exposure;

[0020] (2) mounting the vertical cavity surface emitting laser, the surface receiving detector, the laser driver chip and the transimpedance amplifier chip on the surface of the ceramic substrate respectively by using silver paste, and baking and fixing them in a constant temperature oven;

[0021] (3) pasting the finished ceramic substrate onto an iron sheet using silver paste, and baking and fixing the substrate in a constant temperature oven;

[0022] (4) bonding the optical fiber array in parallel to the surface of the ceramic substrate;

[0023] (5) Encapsulate the ceramic substrate and various components mounted on its surface with epoxy resin;

[0024] (6) Attach heat dissipation silicone grease to the back of the iron sheet and make the heat dissipation silicone grease come into direct contact with the metal casing used to place the printed circuit board.

[0025] Furthermore, the specific steps of step (4) are as follows: a low-shrinkage UV-curing glue is coated on the bottom of the optical fiber array, and then the optical fiber array is coupled with the vertical cavity surface emitting laser and the surface receiving detector. After the coupling is completed, ultraviolet light is used to form a preliminary fixation; then, a refractive index matching glue is filled between the optical fiber on the optical fiber array and the vertical cavity surface emitting laser and the surface receiving detector, and then ultraviolet light is used to cure.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The optical transceiver module of the present invention makes the overall structure of the module more compact, which solves the cost problem and assembly complexity problem of the traditional optical transceiver module that relies on discrete device packaging, has the advantages of high reliability, can achieve low-loss signal transmission, and has strong scalability.

[0028] 2. Compared with traditional discrete optical receiving components, the optical transceiver module of the present invention can effectively reduce costs, greatly reduce the volume of the optical part, and use a ceramic substrate to improve the thermal stability of the entire module.

[0029] 3. The optical transceiver module and packaging method thereof of the present invention have the advantages of high coupling efficiency, low power consumption, convenient assembly, simple heat dissipation design and good heat dissipation performance, etc., and thus can greatly improve the flexibility of the optical design part, such as: convenient integration of wavelength division multiplexing function, etc., and greatly reduce the packaging volume of the optical part. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is an overall effect diagram of the optical transceiver module in the present invention.

[0031] Figure 2 It is a schematic diagram of the three-dimensional structure of the optical transceiver module in the present invention.

[0032] Figure 3 It is a three-dimensional structural schematic diagram of the printed circuit board and the iron sheet in the present invention.

[0033] Figure 4 It is a three-dimensional structural schematic diagram of the printed circuit board, the iron sheet and the ceramic sheet in the present invention.

[0034] Figure 5 It is a schematic diagram of the back three-dimensional structure of the optical transceiver module in the present invention.

[0035] Figure 6 It is a schematic diagram of the ceramic substrate after the gold layer is plated in the present invention.

[0036] Figure 7 It is a schematic diagram of the patch of the vertical cavity surface emitting laser, the surface receiving detector, the laser driving chip and the transimpedance amplifier chip in the present invention.

[0037] Figure 8 It is a side view of the optical transceiver module in the present invention.

[0038] Fig. 9 It is a side view of the optical transceiver module in the present invention from another perspective. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further specifically described below through embodiments in conjunction with the accompanying drawings.

[0040] Embodiment: An optical transceiver module and a packaging method thereof, such as Figure 1-9 As shown, the optical transceiver module includes a fiber array (FA) 1, a ceramic substrate 3, an iron sheet 4, a heat dissipation silicone grease 12, a vertical cavity surface emitting laser 6, a surface receiving detector 5, a laser driver chip 8, a transimpedance amplifier chip 7 and a printed circuit board (PCB) 10, wherein a through groove is provided on the surface of the printed circuit board 10, and the printed circuit board 10 is placed in a metal casing.

[0041] The optical fiber array 1 is supported on a ceramic substrate 3, and the two are bonded together by a low shrinkage UV curing adhesive 14. The ceramic substrate 3 is supported on an iron sheet 4. The iron sheet 4 is located directly below the through slot of the printed circuit board 10, and the iron sheet 4 and the printed circuit board 10 are bonded together by a UV curing adhesive. The vertical cavity surface emitting laser 6 and the surface receiving detector 5 are respectively mounted on the ceramic substrate 3, and the ceramic substrate 3 is plated with a gold layer 3-1 and an alignment mark 3-2 also formed by the gold layer.

[0042] Specifically, the optical fiber array 1 is composed of 12 single-mode optical fibers 2 placed in parallel, the interval between the 12 optical fibers 2 is fixed at 250 μm, the end faces used for coupling are polished to 45°, and the 45° end faces are coated with a metal film 13. In this embodiment, electron beam evaporation method is adopted, and the metal film 13 is composed of gold.

[0043] The iron sheet 4 is attached to the bottom of the through slot on the printed circuit board 10 by UV curing adhesive and exposed to UV light for curing and fixing. In this embodiment, the length and width of the iron sheet are both greater than the length and width of the through slot of the printed circuit board 10 by 3 mm.

[0044] The relative positions of the alignment marks 3-2 on the ceramic substrate 3 are determined by the relative positions of the light holes of the vertical cavity surface emitting laser 6 and the light holes of the surface receiving detector 5, and the two groups of alignment marks 3-2 should be kept on the same straight line. In this embodiment, the spacing of the optical fibers 2 in the optical fiber array 1 is 250μm, so the light hole spacing of the vertical cavity surface emitting laser 6 and the light hole spacing of the surface receiving detector 5 are also 250μm.

[0045] The vertical cavity surface emitting laser 6 and the surface receiving detector 5 are mounted on the alignment mark 3-2 by a high-precision chip mounting instrument, and are bonded to the ceramic substrate 3 by an adhesive; similarly, the laser driver chip 8 and the transimpedance amplifier chip 7 are also mounted on the area of ​​the ceramic substrate 3 plated with the gold layer 3-1 by a chip mounting instrument, and fixed by an adhesive. In this embodiment, the adhesive is silver paste, and after mounting, it needs to be placed in a constant temperature oven for baking for 3 to 4 hours.

[0046] After the ceramic substrate 3 is pasted on the iron sheet 4 (the vertical cavity surface emitting laser 6, the surface receiving detector 5, the laser driving chip 8, and the transimpedance amplifier chip 7) through the mounting, the whole is pasted on the iron sheet 4 through silver paste (at this time, the iron sheet 4 has been fixed directly below the through groove of the printed circuit board 10), and is placed in a constant temperature box to bake the silver paste until it is fixed. The purpose of using silver paste to connect the ceramic substrate 3 and the iron sheet 4 is to enhance heat conduction.

[0047] After the patch of the ceramic substrate 3 is completed and fixed, the optical fiber array 1 coated with the low shrinkage rate ultraviolet curing glue 14 is brought close to the ceramic substrate 3 in the horizontal direction, and the position of the optical fiber array 1 is continuously adjusted until the coupling efficiency is highest. Thereafter, the position of the optical fiber array 1 is no longer adjusted, and the area coated with the low shrinkage rate curing glue 14 is irradiated with an ultraviolet lamp to complete the fixation of the optical fiber array 1.

[0048] After the optical fiber array 1 is fixed, an appropriate amount of refractive index matching glue 15 is filled between the optical fiber 2 in the optical fiber array 1 and the vertical cavity surface emitting laser 6 and the surface receiving detector 5 to improve the coupling efficiency, and then irradiated with an ultraviolet lamp to complete the secondary curing. The vertical cavity surface emitting laser 6 and the surface receiving detector 5 are connected to the flat optical fiber array 1 through the refractive index matching glue 15 to achieve signal transmission.

[0049] After the optical fiber array 1 completes secondary curing, the epoxy resin black glue 11 is then applied to the entire ceramic substrate 3, and the entire ceramic substrate 3 and the optical fiber array 1, vertical cavity surface emitting laser 6, surface receiving detector 5, laser driver chip 8, and transimpedance amplifier chip 7 mounted on the ceramic substrate 3 are packaged to complete the final airtight packaging to enhance the reliability and heat dissipation performance of the module.

[0050] The heat dissipation silicone grease 12 is pasted on the back of the iron sheet 4 after the airtight packaging is completed, so as to form direct contact with the metal shell used to place the entire printed circuit board 10, thereby enhancing heat dissipation.

[0051] The vertical cavity surface emitting laser 6 and the surface receiving detector 5 on the ceramic substrate 3 are electrically connected to the laser driving chip 8 and the transimpedance amplifier chip 7 respectively through gold wire ultrasonic welding.

[0052] The laser driving chip 8 and the transimpedance amplifier chip 7 on the ceramic substrate 3 are electrically connected to the pads around the through-slot of the printed circuit board 10 by gold wire ultrasonic welding.

[0053] The microcontroller chip 9 on the printed circuit board 10 is electrically connected to the pads around the through slot through wiring, thereby completing the electrical connection within the entire transceiver module.

[0054] The optical transceiver module formed by the present invention has the following working principle: the modulated external high-speed electrical signal enters the laser driver chip 8 located on the ceramic substrate 3 through the printed circuit board 10, and the laser driver chip 8 processes the electrical signal transmitted from the outside into an electrical signal suitable for driving the vertical cavity surface emitting laser 6. After being driven by the laser driver chip 8, the vertical cavity surface emitting laser 6 converts the external electrical signal into an optical signal, and transmits it through the optical fiber array 1 to complete the conversion from electricity to light. Similarly, the high-speed modulated optical signal transmitted from the outside to the optical fiber array 1 is received by the surface receiving detector 5, and the optical signal is converted into a weak electrical signal, and then the weak electrical signal is processed by the transimpedance amplifier chip 7 by limiting amplification, gain control, pre-emphasis, etc., so as to form an electrical signal suitable for communicating with the host computer (such as a switch), and complete the conversion from light to electricity.

[0055] The above specific implementation methods are only preferred embodiments of the present invention and are 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 in the protection scope of the present invention.

Claims

1. An optical transceiver module, It is characterized in that The device comprises at least one optical fiber array, at least one ceramic substrate, at least one iron sheet, at least one heat dissipation silicone grease, at least one vertical cavity surface emitting laser, at least one surface receiving detector, at least one laser driver chip, at least one transimpedance amplifier chip, and at least one printed circuit board, wherein the printed circuit board is provided with a through groove, the iron sheet is fixedly arranged on the lower surface of the printed circuit board, the iron sheet is located below the through groove, and the heat dissipation silicone grease is adhered to the back of the iron sheet; The ceramic substrate is fixedly arranged on the upper surface of the iron sheet, the vertical cavity surface emitting laser, the surface receiving detector, the laser driver chip and the transimpedance amplifier chip are respectively mounted on the surface of the ceramic substrate, the optical fiber array is bonded in parallel to the surface of the ceramic substrate, and the ceramic substrate and various components mounted on the surface are covered and packaged by epoxy resin black glue; The vertical cavity surface emitting laser and the surface receiving detector are linked to the optical fiber array through a refractive index matching glue to realize signal transmission, the vertical cavity surface emitting laser is electrically connected to the laser driving chip, the surface receiving detector is electrically connected to the transimpedance amplifier chip, and the laser driving chip and the transimpedance amplifier chip are electrically connected to the printed circuit board respectively; The iron sheet is adhered to the printed circuit board directly below the through slot by means of UV curing adhesive; The ceramic substrate is plated with a gold layer and an alignment mark, the laser driver chip and the transimpedance amplifier chip are mounted on the gold layer, and the vertical cavity surface emitting laser and the surface receiving detector are mounted on the alignment mark; The vertical cavity surface emitting laser, the surface receiving detector, the laser driving chip and the transimpedance amplifier chip are respectively mounted on the surface of the ceramic substrate through silver paste; The ceramic substrate is pasted on the iron sheet by silver paste; The optical fiber array includes a plurality of optical fibers arranged in parallel, the end faces of the optical fibers used for coupling are at an angle of 45°, and the end faces are coated with a metal film to enhance reflection; The printed circuit board is also provided with a microcontroller chip, and the microcontroller chip is electrically connected to the pads on the printed circuit board through wiring; The optical transceiver module also includes a metal shell, the printed circuit board is placed in the metal shell, and the heat dissipation silicone grease pasted on the back of the iron sheet is in contact with the metal shell.

2. The packaging method of the optical transceiver module according to claim 1, It is characterized in that The packaging method comprises the following steps: (1) The iron sheet is adhered to the bottom of the through slot of the printed circuit board by means of UV curing adhesive and fixed by UV exposure; (2) mounting the vertical cavity surface emitting laser, the surface receiving detector, the laser driver chip and the transimpedance amplifier chip on the surface of the ceramic substrate respectively by using silver paste, and baking and fixing them in a constant temperature oven; (3) pasting the finished ceramic substrate onto an iron sheet using silver paste, and baking and fixing the substrate in a constant temperature oven; (4) bonding the optical fiber array in parallel to the surface of the ceramic substrate; (5) Encapsulate the ceramic substrate and various components mounted on its surface with epoxy resin; (6) Attach heat dissipation silicone grease to the back of the iron sheet and make the heat dissipation silicone grease come into direct contact with the metal casing used to place the printed circuit board.

3. The packaging method according to claim 2, It is characterized in that The specific steps of step (4) are as follows: UV curing glue is coated on the bottom of the optical fiber array, and then the optical fiber array is coupled with the vertical cavity surface emitting laser and the surface receiving detector. After the coupling is completed, ultraviolet light is used to form a preliminary fixation; then refractive index matching glue is filled between the optical fiber on the optical fiber array and the vertical cavity surface emitting laser and the surface receiving detector, and then ultraviolet light is used to cure.

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