Crosstalk measurements of monolithic GaAs photoconductive detector arrays in the GHz region

The crosstalk levels among detectors in a monolithic GaAs photoconductive detector array were measured in the frequency range 250 MHz–1.3 GHz. When the array was mounted on a properly designed microstripline circuit, crosstalk levels below −44 dB were achieved at a detector spacing of 100 μm across the entire 1.3-GHz bandwidth. The provision of a ground plane fabricated monolithically with the array was found to be important. The observed −44 dB crosstalk level in the GHz frequency region confirms the feasibility of a completely integrated broadband optoelectronic switching matrix.