Optical propagation losses in thin-film lithium niobate waveguides are measured using the Fabry-Pérot method. A perturbational model attributing losses to sidewall roughness is developed to predict attenuation for different waveguide geometries. The finite-element solver in JCMsuite is used to rigorously compute the guided mode profiles of the idealized, lossless waveguides, which are essential for the loss estimation procedure.
M. Hammer, et al. Estimation of losses caused by sidewall roughness in thin-film lithium niobate rib and strip waveguides. Opt. Express, 32, 22878 (2024).
DOI: 10.1364/OE.521766