Microwave signal switching on a silicon photonic chip

Abstract

Microwave photonics uses light to carry and process microwave signals over a photonic link. However, light can instead be used as a stimulus to microwave devices that directly control microwave signals. Such optically controlled amplitude and phase-shift switches are investigated for use in reconfigurable microwave systems, but they suffer from large footprint, high optical power level required for switching, lack of scalability and complex integration requirements, restricting their implementation in practical microwave systems. Here, we report Monolithic Optically Reconfigurable Integrated Microwave Switches (MORIMSs) built on a CMOS compatible silicon photonic chip that addresses all of the stringent requirements. Our scalable micrometer-scale switches provide higher switching efficiency and require optical power orders of magnitude lower than the state-of-the-art. Also, it opens a new research direction on silicon photonic platforms integrating microwave circuitry. This work has important implications in reconfigurable microwave and millimeter wave devices for future communication networks.

Tunable and reconfigurable bandstop filters enabled by optically controlled switching elements

“…In general, when a semiconductor is illuminated by light, free carriers will be generated as long as the photon energy is larger than the bandgap (e.g. 1.12 eV for silicon) [9][10][11]. As a consequence, the photoconductivity of the semiconductor can be modulated by changing the illumination light intensity.…”