The compressive nature of optical detection in GaAs MESFETs and possible application as an RF logarithmic amplifier

The photodetection mechanisms in GaAs MESFETs have been investigated by several researchers. The authors have previously performed an in-depth study of the MESFET as an optical detector under constant illumination involving both experimental and theoretical modeling. In this work, they discuss the compressive nature of that photodetection process. Experimental results involving constant illumination, modulated light and pulsed illumination verify the theoretical conclusions. A suggested structure for an RF logarithmic amplifier based on the above phenomenon is presented