The Frequency Response Research of Photodetector by Laplace Transform
基于Laplace变换法的光电探测器频率响应研究

Depended on the basic equations of photodetector, the frequency response characteristic of a N-well/P-sub structure photodetector in standard CMOS technology is analyzed by the Laplace transform method.The intrinsic cut-off frequency of this photodetector is 14.4 MHz and 43 MHz in 780 nm and 650 nm wavelength,respectively.Usually,the photodetector bandwidth can only be approximately analyzed by transport time, whose reaction on the whole response time is uncertainty.Also the Laplace method avoids the influence of load circuits in frequency measurement.It is fit for the frequency response research of PN or PIN photodetector.