High-Performance Optically Controlled RF Switches for Advanced Reconfigurable Millimeterwave-to-THz Circuits

In this paper, optically-controlled high-performance integrated RF switches have been proposed, investigated and discussed. The switching is based on the high conductivity change (5-6 orders) due to photo-induced free-carriers in semiconductors. Initial simulation for G-band CPW-based optical switches has shown that a record-high (compared to semiconductor and VO₂ switches) intrinsic FOM (figure of merit evaluated by R_onC_off constant) of 153 THz can be achieved using Ge (85 THz with Si). In addition, the on/off ratio can be maintained as high as 28.1 dB at 200 GHz. The proposed device has not only superior performance, but also the advantages of compact size, easy fabrication and integration, as well as high speed and reliability, making it a great candidate for enabling advanced tunable/reconfigurable circuits that are required in millimeter-wave and terahertz communications.