Ultra-Low Loss 698 nm and 450 nm Silicon Nitride Visible Wavelength Waveguides for Strontium Atomic Clock Applications

We report tightly confining Si 3 N 4 waveguides with record low loss at key strontium clock visible wavelengths, 0.03dB/cm at λ=698nm, 0.08dB/cm at 450nm and ring resonators with measured loaded Q of 8.6 million at λ=674nm.