Tunable microwave photonic phase shifter based on silicon microring resonator

We present an integrated continuously tunable microwave photonic phase shifter based on the strain effects in silicon-oninsulator microring resonators, which eliminates the use of microheaters in conventional phase shifter tuning schemes. We demonstrate the tunability of the radiofrequency phase shift by mechanically inducing a strain-dependent variation in the ring resonator circumference, which causes a subsequent shift in the resonant wavelength and optical phase of the resonator. By applying a small strain, large changes in the radiofrequency phase shifting is demonstrated. As an application example, the proposed strain based microwave photonic phase shifter reveals a phase-shifting of a full range.