Local periodic poling of ridges and ridge waveguides on X- and Y-Cut LiNbO_3 and its application for second harmonic generation

Fabrication, characterization and application of periodical ferroelectric domains in ridges and Ti in-diffused ridge waveguides on X- and Y-cut Lithium Niobate (LN) are reported. The ridge waveguides of 3.5 microm height and 9 microm width were fabricated by inductively coupled plasma (ICP) etching followed by Ti in-diffusion into the ridges only. Appropriate electrodes on their side walls enabled domain inversion restricted to the ridge. The domain structure was investigated by selective chemical etching. Second harmonic generation in a 1.4 cm long ridge waveguide on an X-cut substrate was demonstrated at 1548 nm fundamental wavelength with an efficiency of 17% W(-1).