光电探测电路是光纤通信和光电检测系统中光信号转换成电信号的关键部分,但现有光电探测器大都不能同时测量脉冲光信号与直流光信号。为了获得低噪声并且能够同时测量脉冲光信号和直流光信号的光电探测器,设计一个不隔直光电探测电路,采用平衡放大方式消除直流工作点不稳定问题,提出了一种利用谐波分析法测量光电探测电路带宽的方法;同时对影响噪声的各种因素进行了研究,计算了探测电路的噪声电压和电流,提出了利用降低温度的方法提高信噪比。结果表明了该方法的有效性。 Photoelectric detection circuit is a key part of optical signal conversion into electrical signal in optical fiber communication and photoelectric detection system. However, most of the existing photodetectors can not measure both pulsed light signal and direct light signal at the same time. In order to obtain low-noise and can simultaneously measure the pulsed light signal and the DC light signal photodetector, a non-blocking photodetector circuit design, the use of balanced amplification to eliminate the instability of DC operating point, the use of a harmonic analysis The method of measuring the bandwidth of photodetecting circuit is studied. At the same time, various factors that affect the noise are researched, the noise voltage and current of the detecting circuit are calculated, and the method of reducing the temperature is proposed to improve the signal to noise ratio. The results show the effectiveness of this method.