Monolithic array of optoelectronic broad-band switches

The response of monolithic arrays of GaAs photoconductors to optical intensity modulation signals and their feasibility of operating as crosspoint arrays in integrated broadband switch matrices are investigated. It is found that individual photoconductors can switch signals at frequencies of up to 1.3 GHz with isolation better than 70 dB and switching time less than 10 ns. In a 2×2 monolithic array, 65-dB switch isolation and 80-dB crosstalk isolation between channels are achieved in the frequency range 0-130 MHz. The responsivity is essentially uniform within this frequency range and has a value of 0.84 A/W at 820 nm. At higher frequencies electromagnetic coupling between output lines limits the performance with the layout used. This monolithic array thus demonstrates compact broadband matrix switching of signals in the frequency range up to 100 MHz using the optoelectronic switching principle.