Characterising the linearity of an optically controlled photoconductive microwave switch

The linearity response of a photoconductive switch on microstrip line is presented at 2GHz. A silicon switch is exposed to incident signal power of up to 1W and controlled via illumination with a range of optical intensities at a wavelength of 980nm in order to characterise the linearity in terms of harmonic content. Reported single tone output third order intercept (TOI) was measured as 63dBm under 200mW of optical incident light. The study presents photoconductive switches as a promising alternative to conventional microwave switches in high power applications.