Fabrication and Characterization of waveguides in LiNbO_3 writtenwith femtosecond laser pulses

摘要

The fabrication of waveguides inside transparent media using ultrashort laser pulses has gained a lot of interest during the past years. When femtosecond laser pulses are focused inside the bulk of transparent materials, the refractive-index change can be induced around the focal volume. In this paper, we demonstrate that embedded waveguides are fabricated from a computer-aided design file by scanning the focus spot in z-cut lithium niobate (LiNbO_3) using femtosecond laser pulses. The beam coupling in such waveguides is experimentally investigated. The coupling constant of the waveguide structure is obtained by measuring the ratio of output power of each waveguide.