Supercontinuum Generation in Lithium Niobate Ridge Waveguides Fabricated by Proton Exchange and Ion Beam Enhanced Etching**Supported by the National Natural Science Foundation of China under Grant Nos 61575129 and 11375105, the Postdoctoral Science Foundation of China under Grant No 2016M602511, the Shenzhen Science and Technology Planning under Grant No JCYJ20160422142912923, and the State Key Laboratory of Nuclear Physics and Technology,

Abstract

We report on the fabrication of the 10-mm-long lithium niobate ridge waveguide and its supercontinuum generation at near-visible wavelengths (around 800 nm). The waveguides are fabricated by a combination of MeV copper ion implantation followed by wet etching in a proton exchanged lithium niobate planar waveguide. Using a mode-locked Ti:sapphire laser with a central wavelength of 800 nm, the generated broadest supercontinuum through the ridge waveguides spans 302 nm (at −30 dB points), from 693 to 995 nm. Temporal coherence properties of the supercontinuum are experimentally studied by a Michelson interferometer and the coherence length of the broadest supercontinuum is measured to be 5.2μm. Our results offer potential for a compact and integrated supercontinuum source for applications including bio-imaging, spectroscopy and optical communication.