Optical receiver front-end nonlinear distortion

The harmonic modulation products of a PIN-GaAs MESFET optical receiver front end are found to be about 20 dB smaller than those of a PIN-bipolar transistor front end, using the `two-frequency optical signal method´. It is pointed out that the design parameters in the PIN-GaAs MESFET front end, optimised from the high-sensitivity viewpoint, are compatible with the requirements for low distortion in analogue transmission systems.