A high-speed, large numerical aperture optical field coupling method

Abstract

The application discloses a high-speed and large numerical aperture optical field coupling method and relates to optical communication technology, and comprises the following steps: capturing high-speed optical signals transmitted in space through an optical signal receiving end; the optical signal receiving end adopts a large numerical aperture optical fiber as a receiving end optical signal transmission medium; introducing the optical signals output by the optical fiber receiving end in step 1 into an APD photoelectric detector integrated with a COC microlens system inside, so as to complete directional compression and optical path calibration of the light spot; the effective photosensitive unit of the APD photoelectric detector receives the focused light spot after directional compression in step 2; after the APD photoelectric detector receives the focused light spot, the optical signal is converted into an optoelectronic signal, and optical field coupling is completed. The COC microlens system of the method is directly integrated in the inside of the APD detector package, the receiving aperture does not need to be increased, no precise external components are additionally added, and the advantages of miniaturization and light weight of the laser communication terminal are retained.

Description

Technical Field

[0001] This invention relates to optical communication technology, and more particularly to a high-speed, large numerical aperture optical field coupling method. Background Technology

[0002] In atmospheric space laser communication, atmospheric turbulence is one of the core bottlenecks restricting long-distance transmission performance. Atmospheric turbulence can cause phenomena such as beam phase distortion, spatial offset, and light intensity flicker. Among these, phase distortion directly leads to uneven energy distribution of the beam at the receiving end, severely reducing the coupling efficiency between the optical signal and the receiving device. For high-speed space optical communication systems with single-channel rates greater than 10 Gbps, current technologies typically use single-mode fiber for receiving optical signal coupling. However, single-mode fiber has a small core diameter and low numerical aperture, making it extremely sensitive to beam phase distortion, further amplifying the negative impact of atmospheric turbulence on coupling efficiency and leading to a decrease in system communication stability.

[0003] To address these issues, existing technologies primarily employ two approaches: first, increasing the receiving aperture to collect more light energy and offset energy dispersion caused by turbulence; second, using an adaptive optics system to correct beam phase distortion in real time. However, both approaches have limitations: increasing the receiving aperture significantly increases the size and weight of the terminal system, weakening the core advantages of miniaturization and lightweight design in laser communication terminals; while adaptive optics systems require precision components such as wavefront detectors and deformable mirrors, resulting in high manufacturing costs, complex system structures, and high power consumption, making it difficult to meet the integrated and networked design requirements of space optical communication systems and limiting their application in large-scale communication networks.

[0004] Therefore, there is an urgent need for an optical field coupling scheme that does not require increasing the size of the terminal, has a simple structure, is cost-controllable, can effectively suppress the influence of atmospheric turbulence, and is compatible with multi-rate detectors. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-speed, large numerical aperture optical field coupling method to address the deficiencies in the prior art.

[0006] The technical solution adopted by this invention to solve its technical problem is: a high-speed, large numerical aperture optical field coupling method, comprising the following steps: 1) High-speed optical signals transmitted in space are captured by an optical signal receiver; the optical signal receiver uses a large numerical aperture optical fiber as the optical signal transmission medium. 2) The optical signal output from the fiber optic receiver in step 1) is fed into the APD photodetector, which integrates a COC microlens system, to complete the directional compression of the light spot and optical path calibration: 3) The effective photosensitive unit of the APD photodetector receives the focused light spot after directional compression in step 2); After receiving the focused light spot, the APD photodetector converts the optical signal into a photoelectric signal, thus completing the optical field coupling.

[0007] According to the above scheme, in step 1), the high-speed optical signal is a single-channel optical signal ≥10Gbps.

[0008] According to the above scheme, in step 1), the large numerical aperture fiber is a 50μm large core diameter large numerical aperture fiber, the numerical aperture of the fiber is ≥0.22, and the core diameter tolerance is ≤±1μm.

[0009] According to the above scheme, in step 2), the COC microlens system is integrated into the APD photodetector package through laser welding process, and the optical path coaxiality between the COC microlens system and the APD photodetector is ≤0.1mm.

[0010] According to the above scheme, in step 2), the COC microlens system is integrated into the APD photodetector, and the COC microlens system and the APD chip adopt a coaxial packaging structure.

[0011] According to the above scheme, in step 2), the COC microlens system is integrated inside the input end package of the APD photodetector, adopts an aspherical lens structure, has a focal length of 0.5 to 2 mm, and a spot compression ratio of 3:1 to 5:1. The effective photosensitive area of ​​the APD photodetector is 10 to 15 μm, which matches the output spot size of the COC microlens system.

[0012] According to the above scheme, in step 2), the COC microlens system is an aspherical lens structure with an aspherical radius of curvature of 1.2 mm, a focal length of 1 mm, and a spot compression ratio of 4:1.

[0013] The beneficial effects of this invention are: 1. This invention utilizes a large core diameter to reduce energy loss due to phase distortion of the light spot, a large numerical aperture to improve the ability to capture the offset light spot, and combines microlenses for precise light spot compression, thus solving the problem that coupling efficiency in high-speed optical communication is easily affected by turbulence.

[0014] 2. The COC microlens system of the present invention is directly integrated into the APD detector package, without increasing the receiving aperture or adding precision external components such as wavefront detection, phase correction, and multi-channel phase synthesis. It does not increase the system size and weight, and retains the advantages of miniaturization and lightweight of laser communication terminals. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a flowchart of a method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the method principle of an embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] like Figure 1 and Figure 2 As shown, a high-speed, large numerical aperture optical field coupling method includes the following steps: 1) Capture high-speed optical signals (single channel ≥10Gbps) transmitted in space through the optical signal receiver; the optical signal receiver uses a large numerical aperture optical fiber with a core diameter of 50μm as the optical signal transmission medium. Quartz optical fiber with a core diameter of 50μm and a numerical aperture of 0.22 was selected as the transmission medium, and its end face was polished to reduce light reflection loss. 2) The optical signal output from the fiber optic receiver in step 1) is fed into the APD photodetector, which integrates a COC microlens system. The pre-integrated microlens system is used to perform directional compression of the light spot and optical path calibration. Adaptation of microlens system to APD photodetector; The COC microlens system is integrated into the input end package of the APD photodetector. It adopts an aspherical lens structure with a focal length of 0.5-2mm and a spot compression ratio of 3:1-5:1, ensuring that the 50μm fiber output spot completely covers the effective photosensitive area of ​​the APD after compression. The effective photosensitive area of ​​the APD photodetector is 10-15μm, which is precisely matched with the output spot size of the COC microlens system, and is suitable for the detection requirements of optical signals with a single-channel rate of 10Gbps-100Gbps. In this embodiment, the COC microlens system is fabricated using injection molding, with an aspherical curvature radius of 1.2 mm, a focal length of 1 mm, and a spot compression ratio of 4:1, compressing the spot output from the 50 μm fiber to 12 μm, which is precisely matched with the APD photodetector. Meanwhile, the COC microlens system is integrated into the APD detector package using laser welding technology to ensure optical path coaxiality ≤0.1mm; 3) The effective photosensitive unit of the APD photodetector receives the focused light spot after directional compression in step 2); After receiving the focused light spot, the APD photodetector converts the light signal into a recognizable and processable photoelectric signal, completing the optical field coupling and achieving low-loss, high-stability optical field coupling from the spatial light signal to the detector.

[0018] The method of this invention involves an optical receiving unit receiving spatial optical signals under atmospheric turbulence, transmitting them through a 50μm large-core optical fiber to a COC microlens system, and then coupling the compressed light spot to an APD detector to achieve stable reception of optical signals at rates of 10Gbps-50Gbps with a coupling efficiency of ≥85%.

[0019] This invention overcomes the bottlenecks of volume, cost, and adaptability of existing turbulence suppression schemes through the collaborative design of "large core diameter optical fiber + built-in microlens", providing an efficient and feasible coupling solution for the integration and networking of high-speed atmospheric and space laser communication systems with single-channel speeds of 10Gbps and above.

[0020] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A high-speed, large numerical aperture optical field coupling method, characterized in that, Includes the following steps: 1) High-speed optical signals transmitted in space are captured by an optical signal receiver; the optical signal receiver uses a large numerical aperture optical fiber as the optical signal transmission medium. 2) The optical signal output from the fiber optic receiver in step 1) is fed into the APD photodetector, which integrates a COC microlens system, to complete the directional compression of the light spot and optical path calibration: 3) The effective photosensitive unit of the APD photodetector receives the focused light spot after directional compression in step 2); After receiving the focused light spot, the APD photodetector converts the optical signal into a photoelectric signal, thus completing the optical field coupling.

2. The high-speed, large numerical aperture optical field coupling method according to claim 1, characterized in that, In step 1), the high-speed optical signal is a single-channel optical signal ≥10Gbps.

3. The high-speed, large numerical aperture optical field coupling method according to claim 1, characterized in that, In step 1), the large numerical aperture fiber is a 50μm large core diameter large numerical aperture fiber with a numerical aperture ≥ 0.22 and a core diameter tolerance ≤ ±1μm.

4. The high-speed, large numerical aperture optical field coupling method according to claim 1, characterized in that, In step 2), the APD photodetector, which integrates a COC microlens system, adopts a coaxial packaging structure with the APD chip.

5. The high-speed, large numerical aperture optical field coupling method according to claim 1, characterized in that, In step 2), the COC microlens system is integrated into the APD photodetector package through laser welding, and the optical path coaxiality between the COC microlens system and the APD photodetector is ≤0.1mm.

6. The high-speed, large numerical aperture optical field coupling method according to claim 1, characterized in that, In step 2), the COC microlens system is integrated inside the input end package of the APD photodetector, adopts an aspherical lens structure, has a focal length of 0.5 to 2 mm, and a spot compression ratio of 3:1 to 5:

1. The effective photosensitive area of ​​the APD photodetector is 10 to 15 μm, which matches the output spot size of the COC microlens system.

7. The high-speed, large numerical aperture optical field coupling method according to claim 2, characterized in that, In step 2), the COC microlens system is an aspherical lens structure with an aspherical radius of curvature of 1.2 mm, a focal length of 1 mm, and a spot compression ratio of 4:

1.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1 to 7.

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