Monolithic single-frequency microring laser on an erbium-doped thin film lithium niobate fabricated by a photolithography assisted chemo-mechanical etching

We overcome the difficulty in realizing a monolithic waveguide-coupled microring laser integrated on an erbium-doped thin film lithium niobate (Er: TFLN) using a photolithography assisted chemo-mechanical etching (PLACE) technique. We demonstrate an integrated single-frequency microring laser operating around 1531 nm wavelength. The PLACE technique, enabling integrated Er: TFLN photonics with low propagation loss, can thus be used to realize low cost mass production of monolithic on-chip microlasers with applications ranging from optical communication and photonic integrated circuit (PIC) to precision metrology and large-scale sensing.