Multi-mode optical fiber high-speed light receiving assembly

Abstract

The invention provides a multimode optical fiber high-speed light receiving assembly. The multimode optical fiber high-speed light receiving assembly comprises a tail fiber assembly, a photosensitive diode assembly, a trans-impedance amplifier, a packaging seat and a packaging cap, the transimpedance amplifier is installed on the packaging base and used for converting current output by the photosensitive diode assembly into a voltage signal to be output; the photosensitive diode assembly is installed on the trans-impedance amplifier and used for receiving an external optical signal transmitted by the tail fiber assembly and converting the optical signal into a current signal. The packaging cap covers the photosensitive diode assembly, the mounting surface of the packaging cap and the second end surface of the packaging seat are welded together, and the packaging cap is provided with a through hole for welding and fixing the tail fiber assembly; the tail fiber assembly is welded in the through hole of the packaging cap, is aligned with the photosensitive area of the photosensitive diode assembly, and is used for receiving an external laser signal. The packaging seat and the packaging cap are welded together to provide an airtight space for the transimpedance amplifier and the photosensitive diode assembly.

Description

Technical Field

[0001] The invention belongs to the field of optical receiving components, and in particular relates to a high-speed optical receiving component structure with stable coupling points for space laser communication. Background Art

[0002] The optical receiving component converts optical signals into electrical signals and is one of the indispensable modules in optical communication. The external optical signal enters the module through the optical module pigtail, is converted into a current signal by the internal photosensitive element, and is converted into a differential voltage signal through a transimpedance amplifier.

[0003] In the photodiode component, the area of ​​the photosensitive area is related to the component rate. Generally, the smaller the area of ​​the photosensitive area, the higher the component rate. At the same time, the area of ​​the photosensitive area also affects the difficulty of the component pigtail coupling process. Generally, the smaller the area of ​​the photosensitive area, the greater the coupling difficulty, and the more difficult it is to achieve the ideal coupling efficiency (not less than 0.85A / W 1550nm). The pigtail core diameter is also related to the component coupling efficiency. Generally, the core diameter is smaller than the photosensitive area diameter, and it is easier to achieve the ideal coupling efficiency. At present, high-speed (not less than 20Gb / s) optical receiving components mostly use single-mode optical fibers with a photosensitive area diameter of no more than 25μm, and the pigtails mostly use single-mode optical fibers with a core diameter of 9μm. The photosensitive element and the transimpedance amplifier are encapsulated in an airtight TO package seat to make a component. The small diameter of the pigtail core of this structure is not conducive to space laser communication. The plug-in installation method of the pigtail is loosely coupled, which is prone to coupling displacement under temperature changes or complex mechanical environments. After the coupling displacement occurs, it may cause the module to fail. At the same time, with the development of space laser communications, higher requirements are placed on optical receiving components: large light receiving area, high speed, and temperature stability, in order to adapt to application requirements with harsh temperatures and complex mechanical environments. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in view of the deficiencies in the prior art, a multi-mode optical fiber high-speed optical receiving component is provided to meet the application requirements of space laser communication in harsh temperature and mechanical environments.

[0005] The technical solution adopted by the present invention includes: a multimode optical fiber high-speed optical receiving component, including a pigtail component, a photosensitive diode component, a transimpedance amplifier, a packaging seat, and a packaging cap;

[0006] The transimpedance amplifier is mounted on the package base and is used to convert the current output by the photodiode component into a voltage signal output;

[0007] The photosensitive diode component is mounted on the transimpedance amplifier and is used to receive an external optical signal transmitted by the pigtail component and convert the optical signal into a current signal;

[0008] The packaging cap is covered on the photodiode assembly, the mounting surface of the packaging cap is welded with the second end surface of the packaging seat, and the packaging cap is provided with a through hole for welding and fixing the pigtail assembly;

[0009] The pigtail assembly is welded in the through hole of the packaging cap and aligned with the photosensitive area of ​​the photodiode assembly for receiving an external laser signal;

[0010] The package base and the package cap are welded together to provide an airtight space for the transimpedance amplifier and the photodiode components.

[0011] The pigtail assembly includes an optical fiber, a buffer tube and a capillary; an axial through hole is opened on the capillary, one end of the buffer tube is fixed to the outside of the capillary by means of an epoxy adhesive, with an overlapping length of 1 to 3 mm, and the other end is fixed to the optical fiber by means of an epoxy adhesive; the light-emitting end face of the optical fiber is stripped of the coating layer, metallized, and then welded to the capillary by means of gold-tin solder.

[0012] The buffer tube is provided with an axial through hole and a side wall observation port, and the diameter of the through hole is larger than the outer diameter of the capillary tube.

[0013] The photodiode assembly is provided with a substrate, a photosensitive element, a convex lens, a photosensitive area, a P electrode, two N electrodes and a photosensitive mounting surface;

[0014] The photosensitive element is located above the substrate, the photosensitive area is located on the top of the photosensitive element, and the convex lens is located above the photosensitive area, and is used to converge the light signal emitted from the light emitting end face, and the converged light is projected into the interior;

[0015] The photosensitive area is located below the convex lens and is used to convert the light signal projected into the photosensitive area into a current signal;

[0016] The P electrode and two N electrodes are located on the top surface of the substrate, connected to the back electrode of the photosensitive element through flip-chip welding, and electrically connected to the lead 403 through wire bonding for internal and external electrical signal transmission;

[0017] The photosensitive mounting surface is located on the bottom surface of the substrate and is used for mounting and fixing the photosensitive diode component.

[0018] The optical fiber is a multimode optical fiber with a core diameter of 50 μm or 62.5 μm.

[0019] The optical fiber light-emitting end face is stripped of the coating layer and then metallized, a wedge-shaped microlens is polished and an anti-reflection film is evaporated, and the wedge-shaped lens angle is 35°±5°.

[0020] The photosensitive diode component adopts an APD avalanche diode or a PIN tube, the diameter of the photosensitive area is no more than 25 μm, and the diameter of the convex lens is 60-100 μm.

[0021] The pigtail assembly and the packaging cap are welded together, and the packaging cap and the packaging seat are welded together to achieve airtightness of the assembly.

[0022] The advantages of the present invention compared with the prior art are:

[0023] (1) The pigtail assembly of the present invention adopts multimode optical fiber to increase the light receiving area and improve the coupling efficiency of the spatial laser;

[0024] (2) The light-emitting end face of the multimode optical fiber of the pigtail assembly of the present invention is ground into a wedge-shaped microlens to reduce the area of ​​the emitted light spot and improve the pigtail coupling efficiency;

[0025] (3) A convex lens is provided on the photosensitive region of the photodiode assembly of the present invention to improve the pigtail coupling efficiency; BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the product structure of the present invention;

[0027] Figure 2 is a schematic diagram of a photodiode assembly of the present invention;

[0028] Figure 3 is a schematic diagram of a pigtail assembly of the present invention;

[0029] Figure 4 It is a schematic diagram of the packaging seat of the present invention;

[0030] Figure 5 It is a schematic diagram of the packaging cap of the present invention. DETAILED DESCRIPTION

[0031] The structure of the multi-mode optical fiber high-speed optical receiving component for space laser communication according to the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] like Figure 1 As shown, a multimode optical fiber high-speed optical receiving assembly for space laser communication of the present invention comprises a pigtail assembly 1, a photosensitive diode assembly 2, a transimpedance amplifier 3, a packaging seat 4, and a packaging cap 11, wherein the transimpedance amplifier 3 is fixed on a first end face 401 of the packaging seat 4, the photosensitive diode assembly 2 is fixed on the transimpedance amplifier 3, the pigtail assembly 1 passes through a tail hole 1101 of the packaging cap, and a light emitting end face 501 of an optical fiber 5 in the pigtail assembly 1 is aligned with a convex lens 202 in the photosensitive diode assembly 2;

[0033] The photodiode component 2 and the transimpedance amplifier 3 are fixed with epoxy adhesive;

[0034] The transimpedance amplifier 3 and the package base 4 are fixed with epoxy adhesive;

[0035] The packaging cap 11 and the packaging seat 4 are airtightly welded by laser;

[0036] The pigtail assembly 1 and the packaging cap 11 tail pipe 1101 are welded airtight by soldering;

[0037] Photodiode component 2 such as Figure 2 As shown, it includes a substrate 201, a convex lens 203, a photosensitive area 204, a P electrode 206, two N electrodes 205, and a photosensitive mounting surface 207. The convex lens 203 is located above the photosensitive area 204, and the external light signal is emitted from the light-emitting end face 501 of the optical fiber 5. The light converged by the convex lens 203 is projected into 204; the photosensitive area 204 converts the light signal projected into the photosensitive area into a current signal; the P electrode 206 and the N electrode 205 are both located on the top surface of the substrate 201, and are used for input and output of electrical signals; the photosensitive mounting surface 207 is fixed to the first end face 401 of the packaging seat 4 with epoxy glue, and the convex lens 203, the photosensitive area 204 and the tail hole 1101 of the packaging cap 11 are coaxial;

[0038] Pigtail assembly 1 Figure 3 As shown, it includes an optical fiber 5, a buffer tube 6, and a capillary 7. The capillary 7 is provided with an axial through hole 701. The buffer tube 6 is provided with an axial through hole 601 and a side wall observation port 602. The aperture of the through hole 601 is larger than the outer diameter of the capillary 7. The coating layer of the light-emitting end face 501 of the optical fiber 5 is stripped and metallized, and the stripping length is equivalent to the length of the capillary. The end face is processed into a 35°±5° wedge-shaped microlens by a grinding process, and an anti-reflection film is evaporated. The light-emitting end 501 of the optical fiber passes through the capillary through hole 701 and is exposed for a certain length, generally 0.5 to 2 mm. The optical fiber 5 and the capillary 7 are fixed by welding with gold-tin solder; after welding the optical fiber 5, the capillary 7 passes through the through hole 601 of the buffer tube 6, and one end of the buffer tube 6 and the capillary 7 partially overlap, and the overlapping length is generally 1 to 3 mm. Adhesive is applied to the overlapping part to fix the buffer tube 6 and the capillary 7, and the optical fiber 5 is fixed at the other end of the buffer tube 6. The observation hole 602 is used to observe the filling of the internal adhesive.

[0039] Package seat 4 Figure 4 As shown, it includes a first mounting surface 401 of the packaging seat, a second mounting surface 402 of the packaging seat and a lead 403; wherein the first mounting surface 401 of the packaging seat and the second mounting surface 402 of the packaging seat are integrally formed, and the lead 403 passes through the second mounting surface 402 of the packaging seat and the first mounting surface 401 of the packaging seat in sequence, and is welded to the first mounting surface 401 of the packaging seat through a glass bead; the glass bead is made of high-temperature glass or ceramic material.

[0040] like Figure 5As shown, the packaging cap 11 is covered above the photodiode assembly 2, the packaging cap mounting surface 1102 coincides with the second end surface 402 of the packaging seat 4, the packaging cap 11 is fixed to the packaging seat 4 by laser welding, and the assembled pigtail assembly 1 is fixed to the axial through hole 1101 of the packaging cap with solder;

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. For those skilled in the art, several modifications and replacements can be made to the present invention without paying creative work, and all these modifications and replacements should be included in the protection scope of the present invention.

Claims

1. A multimode optical fiber high-speed optical receiving component, characterized in that: It comprises a pigtail assembly (1), a photosensitive diode assembly (2), a transimpedance amplifier (3), a packaging seat (4) and a packaging cap (11); The transimpedance amplifier (3) is mounted on the packaging seat (4) and is used to convert the current output by the photosensitive diode component (2) into a voltage signal output; the photosensitive diode component (2) is mounted on the transimpedance amplifier (3) and is used to receive the external optical signal transmitted by the pigtail component (1) and convert the optical signal into a current signal; the packaging cap (11) covers the photosensitive diode component (2), the packaging cap mounting surface (1102) and the packaging seat (4) are welded together, and the packaging cap is provided with an axial through hole (1101) for welding and fixing the pigtail component (1); the pigtail component (1) is welded in the through hole of the packaging cap (11) and aligned with the photosensitive area (204) of the photosensitive diode component (2) to receive an external laser signal; the packaging seat (4) and the packaging cap (11) are welded together to provide an airtight space for the transimpedance amplifier (3) and the photosensitive diode component (2).

2. A multimode optical fiber high-speed optical receiving assembly according to claim 1, characterized in that: The pigtail assembly (1) comprises an optical fiber (5), a buffer tube (6) and a capillary tube (7); an axial through hole (701) is opened on the capillary tube (7); one end of the buffer tube (6) is fixed to the outside of the capillary tube (7) by means of an epoxy adhesive, with an overlap length of 1 to 3 mm, and the other end is fixed to the optical fiber (5) by means of the epoxy adhesive; the light-emitting end face (501) of the optical fiber (5) is stripped of the coating layer, metallized, and then soldered to the capillary tube (7) by means of gold-tin solder.

3. A multimode optical fiber high-speed optical receiving assembly according to claim 2, characterized in that: The buffer tube (6) is provided with an axial through hole (601) and a side wall observation port (602); the diameter of the through hole (601) is larger than the outer diameter of the capillary tube (7).

4. A multimode optical fiber high-speed optical receiving assembly according to claim 1, characterized in that: The packaging seat (4) comprises a first packaging seat mounting surface (401), a second packaging seat mounting surface (402) and a lead (403); wherein the first packaging seat mounting surface (401) and the second packaging seat mounting surface (402) are integrally formed, and the lead (403) passes through the second packaging seat mounting surface (402) and the first packaging seat mounting surface (401) in sequence, and is then welded to the first packaging seat mounting surface (401) via a glass bead.

5. A multimode optical fiber high-speed optical receiving assembly according to claim 4, characterized in that: The glass beads are made of high-temperature glass or ceramic material.

6. A multimode optical fiber high-speed optical receiving assembly according to claim 4, characterized in that: The photodiode assembly (2) is provided with a substrate (201), a photosensitive element (202), a convex lens (203), a photosensitive area (204), a P electrode (206), two N electrodes (205) and a photosensitive mounting surface (207); The photosensitive element (202) is located above the substrate (201), the photosensitive area (204) is located on the top of the photosensitive element, and the convex lens (203) is located above the photosensitive area (204) and is used to converge the light signal emitted from the light output end face (501) of the light (5), and project the converged light into (204); The photosensitive area (204) is located below the convex lens (203) and is used to convert the light signal projected into the photosensitive area into a current signal; The P electrode (206) and the two N electrodes (205) are both located on the top surface of the substrate (201), connected to the back electrode of the photosensitive element (202) through flip-chip welding, and electrically connected to the lead (403) through wire bonding, for internal and external electrical signal transmission; The photosensitive mounting surface 207 is located on the bottom surface of the substrate (201) and is used to mount and fix the photosensitive diode assembly (2).

7. A multimode optical fiber high-speed optical receiving assembly according to claim 2, characterized in that: The optical fiber (5) is a multimode optical fiber with a core diameter of 50 μm or 62.5 μm.

8. A multimode optical fiber high-speed optical receiving assembly according to claim 2, characterized in that: The light-emitting end face (501) of the optical fiber (5) is metallized after the coating layer is stripped off, a wedge-shaped microlens is polished, and an anti-reflection film is evaporated, and the wedge-shaped lens angle is 35°±5°.

9. A multimode optical fiber high-speed optical receiving assembly according to claim 6, characterized in that: The photosensitive diode assembly (2) adopts an APD avalanche diode or a PIN tube, the diameter of the photosensitive region (204) is no greater than 25 μm, and the diameter of the convex lens (203) is 60-100 μm.

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