Ultra-low power Si-photonic variable-gap coupler switch with nano-latch mechanism

A Si-nanowire variable-gap coupler switch with a nano-latch mechanism is designed and fabricated for on-chip waveguide circuits in Si-photonics. The designed switch consists of a coupler of two freestanding 400 nm wide 260 nm thick Si waveguides, three 30 μm wide 40 μm long comb-drive actuators, and a nano-latch mechanism. The nano-latch mechanism consists of four hook-shaped latches to hold a switch-on condition at a coupler gap of about 100 nm. The proposed switch is fabricated on a silicon-on-insulator wafer by electron beam lithography. The switching and latching characteristics are measured. The port isolation under the latched condition is measured from infrared camera images. Due to the capacitive operation of the actuators and the nano-latch mechanism, the power consumption of the switch is extremely small comparing with the conventional thermo-optical switches.