Watt-class wavelength conversion is expected by enlarging the mode size of the channel waveguides to dozens of micrometers to avoid optical damage with high-power pump lasers. In this work, uniform periodically-poled (PP) structures in MgO doped stoichiometric LiTaO3 were fabricated by applying voltage with an SiO2 insulation layer. Annealed proton-exchanged waveguides with a full width at 1/e
2 maximum in a width of 43 μm and that in depth of 28 μm were obtained by proton exchanging for 4 h and thermal diffusion for 75 h. This waveguide can be excited by pump waves with a power of 8.6 W considering the optical damage threshold. Second harmonic generation with a wavelength of 515 nm was conducted in the low power region of about 35 mW to investigate the basic characteristics. Normalized wavelength conversion efficiency in the 15-mm-long PP structures was estimated to be 4.3%/W.
We developed deep-proton exchanged (DPE) and annealed waveguides in MgO:stoichiometric-LiTaO3 crystal. We performed DPE in pyrophosphoric acid at 230 °C for 20 min and measured mode size and depth dependent on the annealing duration. High-quality planar waveguides of a mode size as large as 20 µm, suitable for electro-optic spatial light modulators for 355 nm UV wavelength, were obtained by annealing for 200 h.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.