Bistable optically controlled semiconductor switches in a frequency-agile RF source

The processes of persistent photoconductivity followed by photoquenching have been demonstrated at megawatt power levels in copper-compensated, silicon-doped, semi-insulating gallium arsenide. These processes allow a photoconductive switch to be developed that can be closed by the application of one laser pulse (/spl lambda/=1.06 /spl mu/m) and opened by the application of a second laser pulse with a wavelength equal to twice that of the first laser (/spl lambda/=2.13 /spl mu/m). This switch is called the bistable optically controlled semiconductor switch (BOSS). The opening phase of the BOSS requires a sufficient concentration of recombination centers (RC) in the material for opening to occur in the subnanosecond regime. These RC's are generated in the bulk GaAs material by fast-neutron irradiation (/spl sim/1 MeV). Neutron-irradiated BOSS devices have been opened against a rising average electric field of about 36 kV/cm (18 kV) in a time less than 1 ns while operating at a repetition rate, within a two-pulse burst, of about 1 GHz. The ability to modify the frequency content of the electrical pulses, by varying the time separation, is demonstrated. Results demonstrating the operation of two BOSS devices imbedded in a frequency-agile RF source configuration are also discussed.