Tunable self-injection-locked narrow-linewidth laser based on thin-film lithium niobate

We demonstrate an electro-optically tunable narrow-linewidth 1550 nm laser based on thin-film lithium niobate. By self-injecting a 1550 nm seed laser into a high-Q lithium niobate microring resonator, the linewidth of the output laser is significantly narrowed. On-chip integration of microelectrodes is further performed to obtain lowvoltage and wide-spectral tuning, resulting in an electro-optical efficiency of 2.95 pm/V with good linearity. With an applied voltage of -10 to 10 V, the laser can achieve a wavelength tuning capability of -50 pm near 1552 nm. The demonstrated electrooptically tunable laser holds great potential for various applications in optical communications, LiDAR, and spectroscopy.