Nanostructure Effects in Microring-Based Uni-Travelling-Carrier Photodiode

In this paper, we propose a new structure for UTC-PDs to enhance the efficiency and bandwidth simultaneously. Microring UTC-PDs (MRUTC) consist of low absorption active regions, so with regarding the main advantages of both resonant cavity enhanced photodiodes and waveguide photodiodes, they have solved the tradeoff between 3-dB bandwidth and efficiency. It is shown that the nanometer cavities and low absorption structures are suitable for very high speed PDs. It is also shown that this PD can achieve high efficiencies without sacrificing the high-speed characteristics, even with very low absorption and low volume active regions. The fundamental equation for quantum efficiency of MRUTC-PD is derived by solving drift-diffusion equation and the important features of the device such as improvement of efficiency and wavelength selectivity are discussed and some design curves are presented.

Keywords:

Uni-Travelling-Carrier Photodiode (UTC-PD) , Microring UTC-PD (MRUTC-PD) , Quantum efficiency ,