High-Speed Photodiodes

To meet the challenge of broad bandwidth and high-responsivity numerous photodetector approaches have been investigated. Normal-incidence photodiodes have the advantages of relatively simple structures, high responsivity, and relaxed packaging constraints for bandwidths of a few gigahertz. Achieving acceptable responsivity at higher speed necessitates the use of waveguide structures. The emergence of Si photonics has also relied on developing suitable waveguide photodiodes. This paper reviews the technologies employed for high-speed photodiodes and state-of-the-art performance.