Efficient sum-frequency generation of a yellow laser in a thin-film lithium niobate waveguide

Yellow lasers with high efficiency and tunability play an essential role in many applications. Here, we demonstrate the sum-frequency generation (SFG) of yellow light on a periodically poled thin-film lithium niobate (PP-TFLN) waveguide. Taking advantage of large χ⁽²⁾ nonlinearity, a high normalized conversion efficiency of 10,097% (W·cm²) is obtained with pump wavelengths of 1317.7 and 1064 nm. An absolute conversion efficiency of 24.17% is recorded with on-chip pump powers of 10.4 dBm (O-band) and 13.5 dBm (1064 nm).