Development of high-speed P-i-N photodetector for 50Gb/s optical link in data centers

Abstract

Various emerging applications such as high-performance computing (HPC) have been pushing the speed limit of communication. The growing dependence on the optical interconnect in data centers results from its superiority over traditional electrical interconnects to transmit data at high speed over long distance. The P-i-N photodiode, having the advantage of high bandwidth and low noise level, plays a significant role in the receiver end of optical interconnects. The subject of this work is the design, fabrication, measurement and modeling of high-speed GaAs P-i-N photodiodes operating at 50Gb/s. The material structure and device scaling are determined through microwave analysis and simulation. Photodiodes of 20um aperture diameter is fabricated and subsequently characterized, showing both high bandwidth and low noise level. A small signal model is also proposed in support of the measurement results.