A low-bias operational MPDA photodetector with high bandwidth-efficiency product and high saturation characteristics

A low-bias operational modified partially depleted absorber photodetector (MPDA-PD) is proposed in this paper. By adopting gradual doping following Gaussian distribution and inserting a buffer layer, the bandwidth-efficiency product and the saturation characteristics of the traditional partially depleted absorber photodetector (PDA-PD) in the low-bias range (0 similar to 1 V) are optimized. When the thickness of the absorption layer is 1200 nm, the 3-dB bandwidth of the MPDA-PD with the diameter of 8 mu m reaches 59.1 GHz at 0.6 V. The bandwidth-efficiency product of the MPDA-PD reaches 33.98 GHz, which is 40.6% higher than the traditional PDA-PD in the reference. Meanwhile, the direct-current (DC) saturation current of 121.1 mA and RF output power of -12.2 dBm at 50 GHz are obtained.