Robust modal phase matching in subwavelength x-cut and z-cut lithium niobate thin-film waveguides

• 作者: Lingzhi Peng Lihong Hong Baoqin Chen Peng He Zhiyuan Li
• 来源期刊: 中国光学快报（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: Nonlinear Optics
• 页码范围: 72-76
• 页数: 5页
• 语种: 英文
• DOI: 10.3788/COL202119.071902

摘要

We use the nonlinear coupled-mode theory to theoretically investigate second-harmonic generation[SHG]in subwave-length x-cut and z-cut lithium niobate[LN]thin-film waveguides and derive the analytical formula to calculate SHG efficiency in x-cut and z-cut LN thin-film waveguides explicitly.Under the scheme of optimal modal phase matching[MPM],two types of LN thin films can achieve highly efficient frequency doubling of a 1064 nm laser with a comparable conversion efficiency due to very consistent modal field distribution of the fundamental wave and second-harmonic wave with efficient overlap between them.Such a robust MPM for high-efficiency SHG in both the subwavelength x-cut and z-cut LN thin-film wave-guides is further confirmed in a broad wavelength range,which might facilitate design and application of micro-nano non-linear optical devices based on the subwavelength LN thin film.