The OPFET: A new high speed optical detector

A sensitive, high speed optical detector is needed for use in optical communications as well as for laboratory experiments. Recent experiments (1) have shown the GaAs MESFET to be potentially useful as a fast optical detector. We call this device an OPFET. This report summarizes new experimental results which show that the OPFET is both fast and sensitive and which identify the detection mechanism in this structure as photoconductivity. Calculations show that this device should give performance which exceeds that of PIN photo-diodes and rivals avalanche photodiodes. In addition, the structure is easy to integrate for use in optical circuits.