Ultra-low-loss single-mode Si 3 N 4 waveguides with 0.7 dB/m propagation loss

We report an approach to make ultra-low-loss waveguides using fixed-index-contrast stoichiometric Si 3 N 4 . A record low single-mode propagation loss of 0.70 ± 0.02 dB/m was achieved while multi-mode designs have fundamental mode loss as low as 0.43 ± 0.04 dB/m.