激光旋光仪中微弱光信号检测系统的设计与实现

Design ＆ Implementation of Weak Optical Signal Detection System in the Laser Polarimeter

光信号检测是激光旋光仪中一个不可或缺的组成部分。要求检测系统具有较高的测量分辨率、良好的测量重复性、高抗干扰性能和较高的测量精度。在该微弱光信号转换与信号提取系统中，前置放大器和滤波器的设计直接决定了对被检测信号的有效提取，对整个系统性能起着决定性作用。基于此，该系统利用T型电阻网络设计了前置放大器，对输出的微弱信号进行放大；利用双二阶环电路设计了窄带带通滤波器，滤除噪声后对信号进行提取。实验结果表明，该检测系统能将光功率为90nW的微弱光信号转换成幅度为240mV的电压信号，并且有效地抑制了噪声。

Optoelectronic signal detection system is an indispensable part of a laser polarimeter. The detection system should be of high measurement resolution and good repeatability, characterized with high anti-jamming performance and higher measuring accuracy. Design of the preamplifier and the filter plays a decisive role in the performance of the whole optoeleetronic detection system and it will directly affect the effective extraction of the signals detected. Because of this, a proper preamplifier is designed by using T-styled resistance network to enlarge the feeble output signal, and a narrow-band filter is also designed by suing a double secondorder loop circuit to extract useful signal in filtering noise. The experimental results show that the deteetion system can convert the feeble optical signal of 90nW of optical power into voltage signal of 240mV, and can suppress noise effectively,