High-performance resonant-cavity photodetectors

Resonant-cavity photodetectors (RECAPs) can circumvent the tradeoff between quantum efficiency and bandwidth that can limit the performance of conventional photodiode structures. For example, a Si-based RECAP has achieved 65% external quantum efficiency with almost 10x improvement in bandwidth compared to commercially-available Si p-i-n photodiodes. In addition, the wavelength selective spectral response offers potential advantages for applications where filtering is needed such as wavelength division multiplexing (WDM). In this paper, we demonstrate, for the first time, a resonant-cavity, separate absorption and multiplication (SAM) avalanche photodiode (APD). The motivation for using the SAM-APD structure is to achieve single carrier injection into the multiplication region and thus obtain low excess multiplication noise. We also demonstrate a long-wavelength, resonant-cavity photodetector that exhibits a high quantum efficiency and the narrowest spectral-linewidth reported to date.