Modeling and optimization of resonant cavity enhanced-separated absorption graded charge multiplication-avalanche photodetector (RCE-SAGCM-APD)

In this paper, a physical model of the Resonant Cavity Enhanced-Separated Absorption Graded Charge Multiplication-Avalanche Photodetector (RCE-SAGCM-APD) is presented. First, a SPICE model for RCE-SAGCM-APD is presented showing the dependence of the transfer function of this model on the dimensions, the material parameters and the multiplication gain of the photodetector. The results obtained from this SPICE model are compared with published experimental results and good agreement is obtained. The present SPICE model can also be applied to non RCE-APD and to different versions of avalanche photodetectors by modifying its transfer function. The gain-bandwidth characteristic of RCE-APD is studied for different areas and different values of the thicknesses of both the absorption and the multiplication layers. The gain-bandwidth characteristic of RCE-SAGCM-APD is studied for the case of an inductor added in series to the load resistance and better performance is achieved in comparison to the case with no inductance. The photodetector with and without the inductor is optimized to get the best values of thicknesses of both absorption and multiplication layers and also the optimal values of the series inductance. These optimizations are done for different areas of the photodetector, different multiplication gains and also for different load resistances.