Ultra-broadband High Coupling Efficiency Using a Si3N4/SiO2 waveguide on silicon

We demonstrate a coupler with an ultra-broadband high coupling efficiency of 96% at 1550 nm, and > 90% from 1450 nm to 1650 nm experimentally. The coupler also features ease of cleaving and large alignment tolerances of 3.8 μm horizontally and 3.6 μm vertically.