分析了高速空间相干光平衡探测器的电路结构和噪声性能, 明确了平衡探测器的关键技术参数与电路结构之间的关系。采用电阻取样型和双跨阻放大器(TIA)合成型结构设计了两种高速空间平衡光电探测器, 并对其性能参数进行了实验验证。实验显示: 两种高速空间相干光电探测器均可用于高速空间相干探测, 且双TIA型电压合成型平衡探测器比电阻取样型平衡探测器具有更高的探测灵敏度和更好的抗噪声性能。 在通信速率为5 Gbps, 误码率10-8条件下电阻取样型平衡探测器实测最优探测灵敏度为-33.51 dBm, 双TIA型电压合成型平衡探测器实测最优灵敏度为-43.4 dBm。对比Discovery公司通信速率为5 Gbps的平衡探测器产品, 双TIA型电压合成型探测灵敏度提高了近8 dB。结果表明高速空间相干光电探测器的结构研究为创建高灵敏的高速空间相干光通信系统提供了理论基础。

The circuit structure and noise characteristics of a high-speed spatial coherent balanced detector were analyzed, and the dependence of key technical parameters on the circuit structure of the balanced detector was clarified. Two kinds of high-speed spatial balanced photoelectric detectors were designed by using resistance sampling and double TIA (Transimpedance Amplifier) synthesis, and their performance parameters were verified by experiments. The experiments indicate that both kinds of high-speed coherent detectors can be used for high-speed coherent detection, while the detection sensitivity and anti-noise performance from the double TIA voltage synthesis balanced detector are better than those from the resistance sampling type detector. When the communication rate is 5Gbps and the bit error rate is 10-8, the optimal detection sensitivity of resistance sampling type balanced detector is -33.51 dBm, and that of the double TIA synthesis balanced detector is -43.4 dBm, higher nearly 8dB than that of the Discovery's 5Gbps balanced detector. The research on the structure of high-speed spatial coherent photodetector provides a theoretical basis for the establishment of a high-sensitivity and high-speed spatial coherent optical communication system.