Microring resonator-coupled photoluminescence from silicon W~centers

Defect centers are promising candidates for waveguide-integrated silicon light sources. We demonstrate microresonator- and waveguide-coupled photoluminescence from silicon W~centers. Microphotoluminescence measurements indicate wavelengths on-resonance with resonator modes are preferentially coupled to an adjacent waveguide. Quality factors of at least 5,300 are measured, and free spectral ranges closely match expectation. The W~center phonon sideband can be used as a spectral diagnostic for a broader range waveguide-based devices on cryogenic silicon photonic platforms.