High-speed InGaAs based resonant cavity enhanced p-i-n photodiodes

High-speed, high-efficiency photodetectors play an important role in optical communication and measurement systems. The photodiode performance is measured by the bandwidth-efficiency product (BWE) and is limited for conventional vertically illuminated photodiodes (VPDs) due to the bandwidth-efficiency tradeoff. This tradeoff arises from the fact that the quantum efficiency and bandwidth of a conventional VPD, have inverse dependencies on the photoabsorption layer thickness. To overcome the BWE limitation for such conventional VPDs, two alternative detection schemes were offered: edge-coupled photodiodes and resonant-cavity-enhanced photodiodes (RCE-PDs). Both PD structures have demonstrated excellent performances and are potential candidates as photodetectors for future high bitrate optical communication systems. The ease of fabrication, integration, and optical coupling makes the RCE-PD more attractive for high-performance photodetection.