Chirped periodically poled lithium-niobate-on-insulator micro-waveguides for broadband second-harmonic generation
Jiayu Wang, Xiaotian Xue, Jing Qiu, Yongzhi Tang, Rui Ye, Yuting Zhang, Yi‐Wen Huang, Hao Li, Shijie Liu, Yuanlin Zheng, Xianfeng Chen
Abstract
Periodically poled lithium niobate (LN) waveguides based on quasi-phase matching schemes, benefiting from their high nonlinear coefficient ( d 33 ) and strong optical confinement, are widely employed for implementing efficient second-harmonic generation (SHG). Here, we report broadband SHG in z-cut chirped periodically poled lithium-niobate-on-insulator (CPPLNOI) ridge micro-waveguides. Nearly 90-nm-wide SHG at the telecom band is achieved, along with an averaged normalized efficiency of 7.5%/(W·cm 2 ). We also demonstrate simultaneous generation of second as well as cascaded third and fourth harmonics under direct pumping of femtosecond pulses. This work would benefit applications for frequency conversion of a wideband coherent light source.