Long wavelength resonant cavity photodetector based on InP/air-gap Bragg reflectors

We demonstrate a long wavelength resonant cavity photodetector with InP/air-gap Bragg reflectors, which is fabricated by using selective wet etching. The peak quantum efficiency is 59% at 1510 nm. A 3-dB bandwidth of 8 GHz has been achieved with the active area of 50×50 μm
²
. Compared with the detector of same absorption depth, a three-fold increase of absorption efficiency is obtained at resonant wavelength.