Wavelength changing device and laser beam generating apparatus

摘要

A wavelength changing device consists of a substrate made of LiTaO<Sub>3</Sub>, an optical waveguide extending in a central upper side of the substrate for transmitting 860 nm wavelength coherent light radiated from a semiconductor laser, a plurality of inverted polarization layers in the substrate, a dielectric film and a plurality of gratings periodically arranged on the dielectric film at regular intervals. The optical waveguide is formed according to a proton-exchange process. The gratings are made of photoresist material having a refractive index N1=1.5 and a high workability, and the gratings are uniformly formed according to an interference-exposure process.

A periodic change in the refractive index is generated in a periodic structure of the gratings and the covering layer, and a part of the coherent light is reflected by the periodic structure to fix the wavelength of the coherent light radiated from the semiconductor laser.