Optical Actuation Performance of Phase-Change RF Switches

Optical actuation of GeTe-based radio frequency switches is studied for the first time at 915-nm optical wavelength. By inducing self-heating of the phase change material through light absorption, this approach removes the need for integrated micro-heaters. First, laser pulse conditions required to set the RF switches in ON-and OFF-states are found with optical pulse peak powers up to few hundred mW. Amorphization is obtained for optical pulses of 100 to 500 ns, and crystallization for pulses of 2 to
$6~\mu \text{s}$
. A resistivity ratio of 2E4 is measured between both states. Cycling endurance is performed on a
${4}\times {5}\,\,\mu \text{m}^{{2}}$
switch, overpassing 1500 cycles, which is much higher compared to previously reported optical demonstrations. Small-signal measurements show 10% lower OFF-state capacitances using optical actuation compared to electrical actuation through micro-heaters. 37 dBm power handling capability is reported in the switch OFF-state at 915 MHz. This optical actuation demonstration corresponds to a standard wavelength in integrated photonic circuits and thus, this work constitutes a first step towards a CMOS compatible fully-integrated optical actuation solution for RF switches based on phase-change material.