Systematic Analysis of a Modified Uni-Traveling-Carrier Photodiode under High-Power Operating Conditions

We theoretically analyzed the detailed carrier transport process based on the drift-diffusion model in the InGaAs/InP modified Uni-Traveling-Carrier Photodiode (MUTC-PD) under high optical input power conditions. A high-speed MUTC-PD design was simulated in depth using the commercial simulation software APSYS. The complex interplay between photo-electron and hole transport processes was quantitatively analyzed. The slowdown of hole transit time due to E field reduction in the undoped InGaAs absorber layer dominated the response speed of MUTC-PDs at a high optical power level. The optimized MUTC-PD design has a relatively strong dependence on optical power level. Based on an optimized design, an O-E conversion responsivity around 0.15 A/W and the intrinsic 3 dB bandwidth of 172 GHz were demonstrated when the input optical power density reached 20 mW/mu m(2). Our simulation analysis results presented here can be utilized for designing broadband MUTC-PDs in future sub-Terahertz free-space data link applications.