High-index-contrast single-mode optical waveguides fabricated on lithium niobate by photolithography assisted chemo-mechanical etching (PLACE)

Abstract

We report fabrication of low loss infrared single mode (1550 nm) waveguides on lithium niobate on insulator cladded by a layer of SiO2. Our technique, termed photolithography assisted chemo-mechanical etching, relies on patterning of a chromium film into the mask shape by femtosecond laser micromachining and subsequent chemo-mechanical etching of the lithium niobate thin film. The high-index-contrast single mode waveguide is measured to have a propagation loss of 0.130 ± 0.008 dB cm−1. Furthermore, waveguide tapers are fabricated for boosting the coupling efficiency.