Triggering GaAs lock-on switches with laser diode arrays

The authors describe the progress that has led to the triggering of high-power photoconductive semiconductor switches (PCSSs) with laser diodes. An 850 W optical pulse from a laser diode array has been used to trigger a 1.5 cm long switch that delivered 8.5 MW to a 38.3 Ω load. Using 166 W arrays, a 2.5 mm long switch has been triggered, delivering 1.2 MW with 600 ps risetimes at pulse repetition frequencies of 1 kHz. These 2.5 mm long switches were tested for pulse lifetime and survived 10⁵ pulses at 1.0 MW levels. In single pulse operation up to 600 A has been switched with laser diode arrays. The goal is to switch up to 5 kA in a single shot mode and up to 100 MW repetitively at up to 10 kHz. It is pointed out that these goals are feasible since the switches can be used in parallel or in series