Electro-optic measurement of GaAs switch voltage during optically activated avalanche

The dynamic turn-on voltage of a bulk GaAs photoconductive switch in a microstrip transmission line was measured for the first time using the electro-optic effect of the switch itself. The technique used a 905 nm laser trigger synchronized with a pulsed 1.06 /spl mu/m probe beam. The GaAs voltage was found to collapse through zero following avalanche and depletion of the transmission line charge. A circuit model including contact lead inductance and an assumed rapid device recovery is developed which produces qualitative agreement with experimental observations.<
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