Integrated Optical Devices in Lithium Niobate

Abstract

Various types of integrated optical devices have been fabricated in lithium niobate (LN), which has excellent electro-optical, acousto-optical and nonlinear properties. Optical channel waveguides of very low propagation losses have been fabricated through the use of the reliable technique of Ti-indiffusion. The inductively coupled plasma-reactive ion etching technique is optimized to fabricate 1.5 μm wide photonic crystal waveguides in a proton-exchanged surface layer of LN. Arrays of up to 101 coupled single-mode guides have been developed, which have led to peculiar properties for linear light propagation and have yielded new results for nonlinear propagation. Ring resonator is also fabricated in LN for rotation rate sensing with a diameter of 60 mm. It consists of a low-loss Ti:LN waveguide ring cavity and a straight waveguide tangential to the ring forming a directional coupler.