Adiabatic thermo-optic Mach–Zehnder switch

In this Letter, we propose and demonstrate a high-speed and power-efficient thermo-optic switch using an adiabatic bend with a directly integrated silicon heater to minimize the heat capacity and therein maximize the performance of the thermo-optic switch. A rapid, τ=2.4  μs thermal time constant and a low electrical power consumption of Pπ=12.7  mW/π-phase shift were demonstrated representing a Pπτ product of only 30.5  mW·μs in a compact device with a phase shifter of only ∼10 μm long.