Characterization and optimization of photonic devices fabricated using femtosecond laser micro-matching

Abstract

There is a great deal of interest and activity in the area of femtosecond micromachining of transparent materials. It promises to be a powerful technique for rapid fabrication of photonic devices in three dimensional geometries. Our group has fabricated and investigated an array of two dimensional and novel three dimensional photonic devices that are able to perform their intended functions but whose loss properties are not yet well known. The first aim of this Masters thesis is to study waveguide loss. It will focus on studying and characterizing the losses of straight and circularly curved waveguides - the building blocks of many practical devices. With a proper understanding of the loss per unit length, per unit bend angle, and per re-write of the waveguides a structured set of guidelines for device fabrication for our particular setup can be made. The second aim of this thesis is the characterization of the photonic devices fabricated and demonstrated by the author. These include a broadband characterization of directional and X couplers, as well as a demonstration of 3D symmetrical 1 :N waveguide splitters for optical signal distribution. These experimental results and discussions, which form the core of the thesis, flow in a logical fashion - from the elemental straight waveguides to the curved waveguides that are used to design the directional couplers. The X couplers provide the broadband performance that the directional couplers cannot and the 1 :N waveguide splitters fabricated with the aid of an improved experimental setup not only provide a more elegant re-design of the broadband X couplers but also demonstrate scalability to N output ports in three dimensions.