Development and testing of bulk photoconductive switches used for ultra-wideband, high-power microwave generation

The Air Force Phillips Laboratory, in collaboration with the Army Research Laboratory (ARL), is developing lateral geometry, high-power photoconductive semiconductor switches (PCSS) for use in phased-array, ultra-wideband (UWB) sources. The current switch utilizes an opposed contact geometry with a 0.25 cm gap spacing and is an extension of previous work on 1.0 cm PCSS devices. This work presents the development and demonstration of the 0.25 cm PCSS under both ideal laboratory conditions and potential source conditions. The laboratory configuration consists of two high-bandwidth transmission lines connected with a PCSS. The potential source configuration consists of a vector-inversion pulse generator (Blumlein) commuted with a PCSS. Independent, low-jitter PCSS operation is demonstrated by series coupling two independent Blumleins into a common load. The 0.25 cm PCSS is shown to operate at 20 kV charge voltage. 65 ps RMS switching jitter, less than 450 ps risetime and greater than 1 kHz pulse repetition rate (PRR) when triggered using a compact, high-power laser diode.