1 mW/π-level InP-based microheaters with sub-microsecond response achieved by pulse-driving

We present an ultra-efficient microheater on a sub-micron-thick InP membrane, designed with direct waveguide heating by an epitaxially grown, vertical dual-layer structure. With minimized heat capacity and thermal leakage, this design achieves a phase tuning efficiency of 1.11 mW/π, switching time of around 10 µs, and a tuning range of more than 3π within a functional length of 19 µm. We then demonstrate one order of magnitude further speed enhancement by an improved pulse-driving method, which minimizes the output optical signal distortion, pushing the switching down to 870 ns.