A Large Signal Equivalent Circuit Modeling and Enhanced RF Output Power of PIN Photodiodes

The photodiode (PD) model in the recently reported works is based on a specified bias condition, which can not fully characterize the state of PD under large signal excitation. A large signal equivalent circuit model consisting of nonlinear resistors and capacitors is proposed to solve the problem. The nonlinear resistors and capacitors describe the PD's electron diffusion effect, junction capacitance, and heterojunctions under different reverse bias and optical power condition. An impedance matching network is proposed based on this model, leading to an enhanced RF output power more than 2.2 dB from 10.4 GHz to 11 GHz. The measured results proves the model well.