Integratable microwave photonic phase shifter based on a tunable optical coupler

Abstract

We propose a novel microwave photonic phase shifter (MWP-PS) architecture which is suitable for on-chip integration. The MWP-PS consists of a laser source, two identical phase modulators (PMs), a tunable optical coupler (TOC), an optical filter and a photodetector (PD). By introducing a microwave signal and its reversed counterpart to the two PMs, respectively, and using the optical filter to remove one of the generated sidebands, a phase shift with its value tuned by the coupling coefficient of the TOC will be introduced to the microwave signal after the PD. A proof-of-concept experiment is carried out. An MWP-PS with a 360° phase shift tuning range and an operational frequency range of 8-40 GHz is achieved.