Intensity modulator based on femtosecond laser assisted waveguide fabrication inside X-cut LiNbO3 crystal

Abstract

This work represents the development of waveguide based linear intensity modulator in X-cut LiNbO 3 wafer. We report on fabrication of optical waveguide structures in X-cut lithium niobate crystal with femtosecond laser direct writing method. Change in refractive index profile is measured using near field intensity profile measurement method for the optimized writing condition. It has been observed that change refractive index (Δn) is 10-4 and the corresponding electro-optic effect at 632.8 nm and 1550 nm is also measured by patterning electrode structure on the substrate. Experimental results indicate that this scheme can be further improved for achieving optical waveguide- based high-speed modulators, optical sensors on X-cut LiNbO3 crystal.