Microwave Phase Shifting Using Coherent Photonic Integrated Circuits

An optically coherent silicon-on-insulator circuit for microwave phase shifting is presented. Such photonic integrated circuits provide advantages over more-complicated incoherent methods and coherent techniques implemented in bulk fiber-optic components. The circuit is described theoretically with supporting experimental data. Continuous microwave phase control at 49 GHz is demonstrated, with an electrical power to achieve 2π phase shift of 80 mW and a 3-dB phase modulation bandwidth of 170 kHz.