| (a) Schematic of the birefringent racetrack resonator on X-cut TFLN, where SH-band light experiences a mode-hybridization in the half-circle waveguide. (b) Principle of SQPM. Inset: varying SQPM SHG intensity with the periodically inverted efficient nonlinear coefficient (m=5), and a comparison among the SHG processes under the perfect phase-matching (PPM), QPM, SQPM, and phase mismatching (PMM). (c) Effective refractive indices of the hybrid mode in SH-band and TE0 mode in FW-band in the half-circle waveguide, and the vector mismatch dispersion between them. (d) Average vector mismatch dispersion versus different FW wavelengths, which is positive in the straight waveguide and negative in the half-circle waveguide. Credit: T. Yuan, J. Wu, et al., doi 10.1117/1.AP.6.5.056012. |
