High Gain-Bandwidth InP Waveguide Phototransistor

We present a high speed phototransistor with integrated waveguide based on our InP double hetrojunction bipolar transistor (DHBT) process technology. We measured an optical-gain cutoff frequency Fopt of 447 GHz with an internal optical gain of over gopt=30 at a base current of Ib=650 µA using devices with emitter dimensions of A=0.7 x 4 µm2.