Current pumped photo-parametric amplifier

This communication describes a photoparametric amplifier based on the current dependency of the depletion layer capacitance of a back biased p-n junction. The charge carriers generated by the photons incident on the diode alter the charge distribution in the vicinity of the depletion layer and cause a change in the capacitance of the junction. This purely reactive effect can be amplified by parametric pumping and leads to a photodetector that combines low output impedance, wide bandwidth and high sensitivity. Experimental results obtained with such a photoparametric amplifier at megacycle modulation frequencies are given. The current dependence of the depletion layer is analyzed and the optimum design of diodes for the amplifier is discussed.