Efficient watt-level 0.775 μm SHG and 3.3 μm DFG in annealed and reverse proton exchanged diced PPLN ridge waveguides

We report on the fabrication of ridge waveguides formed in congruent periodically poled lithium niobate (PPLN). The were fabricated by periodic poling, proton exchange, subsequent annealing and reverse exchange followed diamond blade dicing. Up to 1 W single-pass second-harmonic generation at 775 nm has been realized 50 mm long with internal conversion efficiency 70%. Furthermore, difference frequency 3.3 μm two pump waves 1.05 1.55 obtained similarly PPLN an appropriate poling period.