A microelectromechanically tunable microring resonator composed of freestanding silicon photonic waveguide couplers

A tunable silicon photonic microring resonator using a microelectromechanical actuator is proposed. The tunable microring consists of freestanding submicron-wide single-mode waveguides and air-gap couplers. The waveguides are 320 nm in width and 340 nm in thickness. The optical path length of the microring is varied by a displacement of the actuator. The round-trip length of the microring was modulated by 1.7% with the displacement of 1.0 μm, which corresponded to the resonant wavelength shift of 10.0 nm around 1.5 μm wavelength. The rate of the resonant wavelength shift was 1.1 nm/V. The quality factor of the fabricated microring was about 4000. The whole size of the tunable microring with actuator was about 80 μm × 100 μm and the power consumption is negligibly small due to the capacitive operation.