Limitation factor of the bandwidth for InGaAs/InP monolithic photoreceivers

The authors demonstrate a limiting factor on the bandwidth for InGaAs/InP monolithic photoreceivers that achieves the effect of shortening the gate length. The bandwidth is compared for three types of receivers. The output resistance of the FETs integrated in the receivers is measured, and a drastic reduction in the frequency range from 10 Hz to 1 kHz is observed. This reduction is thought to be caused by traps existing at the interface between the substrate and the FET channel. Considering this effect, the frequency characteristics of the three types of receivers agree well with the results of computer simulation. The factors that limit the 3-dB bandwidth on the amplifier side are also clarified. >