ACTIVE PHOTONIC DEVICES IN LITHIUM NIOBATE DESIGN, FABRICATION AND CHARACTERIZATION

Abstract

Lithium niobate is a commonly used material for optical applications due to its variety of useful optical properties, making it an ideal choice for photonic integrated circuits. However, conventional fabrication techniques produce small associated index increase, precluding compact structures due to prohibitive bending losses. Additionally, lithium niobate is resistant to etching, and produces rough sidewalls when etched, thus patterned micro-structures are prone to high optical losses. In this thesis, we aim to improve the toolset for lithium niobate as an integrated photonics platform. We explore various methods for fabricating devices in lithium niobate, such as titanium diffusion, argon-ion etched structures and lithium niobate-on-insulator. We design and fabricate various optical devices such as waveguides, resonators and modulators. We characterized and evaluated these devices for commercial applications. We seeks to overcome some of the challenges posed by lithium niobate, paving the way for commercial compact and integrated optoelectronic devices in lithium niobate.