Variable-gap silicon photonic waveguide coupler switch with a nanolatch mechanism

Design and fabrication of a variable-gap waveguide coupler switch with a nano latch mechanism are reported for on-chip waveguide circuits in Si photonics. The proposed 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 nanolatch mechanism. The nanolatch mechanism consists of four hook-shaped latches for maintaining a switch-on state at a coupler gap of around 100 nm. The switching and latching characteristics are investigated. The port isolation under the latch-on condition is found to be 17 dB. Due to the capacitive operation of the actuators and the nanolatch mechanism, power consumption of the switch is minimized.