光电探测器的设计

Design of photodetector

分析了硅光电二极管的基本结构、等效电路、噪声等情况。为了提高测量时的线性，要选取Ｒｄ大、Ｒｓ小、ｉ０小的硅光电二极管，并在输出短路状态下工作。因此常采用将运算放大器接成电流－电压转换器的办法来满足这一要求。分析了运算放大器的噪声电压、噪声电流、失调电压、失调电流和硅光电二极管的噪声因素对硅光电二极管与运算放大器组合电路的影响。考虑这些因素可以设计出响应快、灵敏度高、稳定度好、测量线性好、信噪比高的探测器。

In this paper we analyze the structure,equivalent circuit,and the source of noise for the silicon photodiode.In order to improve the measuring linearity,we should choose a silicon photodiode with high R d and I 0 and under output short-circuit operation state by means of turning the operational amplifier into a current-voltage transfer mode.We also analyze the effect of input noise voltage and current,input offset voltage and current of the operational amplifier,and the noise of the silicon photodiode on the combined circuit of the operational amplifier with the silicon photodiode.Taking theses factors into account,we can design detectors with fast response,high sensitivity,good stability,perfect linearity,and high SNR.