Chinese Optics Letters, 2021, 19 (7): 071902, Published Online: Apr. 2, 2021
Robust modal phase matching in subwavelength x-cut and z-cut lithium niobate thin-film waveguides Download: 685次
lithium niobate thin film modal phase matching nonlinear coupled-mode theory second-harmonic generation
Abstract
We use the nonlinear coupled-mode theory to theoretically investigate second-harmonic generation (SHG) in subwavelength 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 waveguides is further confirmed in a broad wavelength range, which might facilitate design and application of micro–nano nonlinear optical devices based on the subwavelength LN thin film.
Lingzhi Peng, Lihong Hong, Baoqin Chen, Peng He, Zhiyuan Li. Robust modal phase matching in subwavelength x-cut and z-cut lithium niobate thin-film waveguides[J]. Chinese Optics Letters, 2021, 19(7): 071902.