Low-loss D-shape Silicon Nitride Waveguides Using a Dielectric Lift-off Fabrication Process

D-shape Si 3 N 4 waveguides are fabricated by dielectric lift-off process. We measure ultra-low loss for a 90nm-thick core of 2.42 dB/m at 1550 nm and a loaded Q-factor of 1.12×106 for a 0.8 mm radius resonator.