High power RF generation with optically activated bulk GaAs devices

The direct generation of high-power radio frequencies was demonstrated, utilizing sections of charged transmission line cables and optically activated semiconductor (OAS) switches. A Q-switched Nd:YAG laser was used to switch an array of GaAs semiconductors, biased at 2 kV DC, resulting in a peak RF output of 7.0 kW at VHF (30 MHz). The maximum current achieved was approximately 12 A, with a pulse width of about 100 ns, instead of the anticipated values of 20 A and 67.5 ns. The longer pulse width, as well as the lower current amplitude, are caused primarily by inductance in the connections between OAS devices.<>