高速智能光纤通信系统和网络的飞速发展对光电探测器提出了更高要求。利用严格耦合波(RCWA)理论，给出了在亚波长光栅(SWG)下方具有分布布拉格反射镜(DBR)结构的理论分析模型，将这种结构作为反射镜应用于谐振腔增强型光探测器(RCE PD)的设计中。仿真表明由于SWG的引入，只需要4对λ/4厚度的InGaAsP/InP系DBR，可使整体膜系结构实现在中心波长1.55 μm处反射率达到99.7%，在1.40 μm至1.62 μm范围内反射率高于99%。引入SWG后的RCE PD在1.55 μm附近的量子效率接近90%，串扰衰减系数与量子效率的乘积超过15 dB。有效地解决了InGaAsP/InP介质膜系DBR 作为谐振腔反射镜反射率低、反射带宽窄的问题。

The model of subwavelength grating (SWG) with several dielectric layers under it is established based on the rigorous coupled-wave approach (RCWA). SWG is introduced as reflectors to the InP based long wavelength resonant cavity enhanced photodetector (RCE PD) design. Simulation demonstrates InP based SWG’s reflectivity is lager than 99.7% in the center wavelength 1.55 μm and wide reflection bandwidth (the reflectivity is higher than 99% from 1.40 μm to 1.62 μm) is achieved at the same time. Compared with pure DBR , the total number of reflector's layers is no more than 9 (4 pairs of DBR and one SWG). Thus it is an innovation of designing long wavelength RCE PD by SWG reflector (SWG-RCE PD) instead of DBR. And the results of simulation show that SWG-RCE PD’s quantum efficiency is about 90% at 1.55 μm and the product of crosstalk attenuation and quantum efficiency is more than 15 dB.