Ultra-Wideband Silicon Plasma Switches

Abstract

The design, optimization, and characterization of an ultra-wideband solid-state plasma shunt switch with state-of-the-art performance is presented, achieving up to 5× reduction in dc power consumption, 4× faster switching speeds, and 2× smaller footprint compared to prior work. The switch is realized by patterning a coplanar waveguide transmission line on a high-resistivity silicon substrate and illuminating the gaps with up to three fibers, creating a highly efficient shunt switch. For efficient power consumption, multiple bias fibers are incorporated to distribute the light avoiding photoconductive saturation. Furthermore, to enhance agility, silicon micromachining is employed, achieving single-digit microsecond switching times under 2.75 µs, the fastest ever recorded for this technology. The result is an ultra-wideband dc-110+ GHz shunt switch with less than 0.81 dB insertion loss and up to 71 dB isolation. This is accomplished with a straightforward manufacturing process in a compact footprint of less than 0.057 mm$^{2}$, paving the way for seamless technology integration. Lastly, highly accurate wideband co-simulations for solid-state plasma modeling are discussed and validated against measurements, underscoring the superior performance and reliability of this disruptive technology.