A silicon microring resonator with a nanolatch mechanism

A microring resonator with a waveguide latch mechanism is designed and fabricated on silicon-on-insulator wafer as switchable notch filter. The waveguide is 400 nm in width and 260 nm in thickness. The latch mechanism consists of three ultrasmall electrostatic comb-drive actuators with nano hooks. One of the actuators is used for moving busline waveguide to the microring and the other two actuators are used for latching the busline waveguide. The busline waveguide is decoupled from the microring in the switch-off state, and it is coupled to the microring in the switch-on state to filter at the resonant wavelength. The position of the busline waveguide is hold by the hooks of latches without applying voltage. The gap between the busline waveguide and the microring was approximately 108 nm after latching, which corresponded to an undercoupling condition of the microring resonator. Applying another voltage to the two latch actuators, the busline waveguide was released and returned to the initial switch-off state. The proposed nanolatch mechanism is useful for reconfigurable photonic circuits using microring resonators.