We carried out second-harmonic generation in quasi-phase-matched alpha-phase lithium niobate channel waveguides realized by proton exchange and surface periodic poling. Owing to a limited ferroelectric domaindepth, we could observe the interplay between second-harmonic generation and self-phase modulation due to cascading and cubic effects, resulting in a nonlinear resonance shift. Data reduction allowed us to evaluate both the quadratic nonlinearity in the near infrared as well as the depth of the uninverted domains.
- Statistical and Nonlinear Physics
- Atomic and Molecular Physics, and Optics