硅基波导共振增强型光电探测器的设计与模拟

Design and Simulation of Si-Based Resonant-Cavity-Enhanced Waveguide Photodetectors

SiGe是间接带隙材料,吸收系数非常小,因而SiGe探测器在红外波段的量子效率很低.本文提出一种新型的探测器结构,即波导共振增强型光电探测器,该器件主要由两个介质布拉格反射镜和波导吸收区构成,器件尺寸较传统波导型探测器大为减小,吸收区的长度不受SiGe临界厚度的限制,实现了量子效率和响应速度的优化.本文在数值模拟的基础上,对器件结构进行了优化设计,结果表明7·6μm长的波导探测器可以得到20%以上的量子效率.

We propose a novel SiGe resonant-cavity-enhanced photodetector that operates at 1.3μm. The device is composed of two Bragg reflectors and a waveguide absorption region. Compared to conventional waveguide photodetectors, the device can be designed with a small enough area for high-speed operation. The limitation of the SiGe critical thickness is circumvented, and the photodetector is expected to have high quantum efficiency. The structure is optimized through numerical simulation and a quantum efficiency of 20% is expected with a 7.6μm-long waveguide.