High-saturation current wide-bandwidth photodetectors

This paper describes the design and performance of two wide-bandwidth photodiode structures. The partially depleted absorber photodiode utilizes an absorbing layer consisting of both depleted and undepleted In_0.53Ga_0.47As layers. These photodiodes have achieved saturation currents (bandwidths) of >430 mA (300 MHz) and 199 mA (1 GHz) for 100-μm-diameter devices and 24 mA (48 GHz) for 100-μm² area devices. Charge compensation has also been utilized in a similar, but modified In_0.53Ga_0.47As-InP unitraveling-carrier photodiode design to predistort the electric field in the depletion region in order to mitigate space charge effects. For 20-μm-diameter photodiodes the large-signal 1-dB compression current and bandwidth were ∼90 mA and 25 GHz, respectively.