  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.
