Accurate semi-empirical model for annealed proton exchanged waveguides in z-cut lithium niobate

An accurate method to estimate the proton dose after PE by applying a soft anneal step was developed. The resulting method can be used to predict phase-matching with 1-2 nm precisions for all devices fabricated with soft anneal depths between 1 and 2 μm and annealed at temperatures 300-360°C to surface concentration is C<0.6 without any parameter adjustments.