Less than 1 dB per meter propagation loss of silica waveguides measured using a ring resonator

Phosphorus doped silica on silicon waveguide propagation loss, bend loss and their polarization dependence have been measured using a set of different radii ring resonators. For a 30 mm ring radius a finesse of 132 was measured and the inferred propagation loss was 0.85 dB/m, the lowest value yet reported. To characterize the finesse of the high Q resonator we proposed and used for the first time a stable Er⁺³ fiber grating laser source which was thermally tuned. This configuration provides improved and accurate measurements capability for finesse values in the range well beyond 100