Photonic crystal fibres and their applications in the nonlinear regime

Abstract

This thesis presents several advances in the technology and applications of photonic crystal �bres achieved over the last three years. Chapters 1 and 2 give the background material important to understand the results presented in chapters 3, 4 and 5. In chapter 1, linear properties of optical �bres are described. This chapter focuses particularly on how the engineering of the cladding structure of solid core photonic crystal �bres can be used to vary the �bre properties, most importantly the group index and dispersion. Propagation in all-solid photonic bandgap �bres is also discussed in terms of the anti-resonant re ecting optical waveguide model. Chapter 2 introduces the nonlinear optical e�ects that are important to understand the work presented in chapters 4 and 5. In chapter 3, a method to reduce bend losses in all-solid photonic bandgap �bres is outlined. The reduction of these losses is achieved by redesigning the high-index inclusions in the cladding structure to suppress cladding modes that strongly couple to the fundamental core-guided mode when the �bre is bent. In chapter 4, a method of tapering photonic crystal �bres in order to decrease the dispersion along their length is described. The tapers are used to compress solitons via adiabatic soliton compression and a combination of adiabatic soliton compression and soliton e�ect compression, achieving a factor of 15 compression of a transform-limited pulse to below 50 fs. Chapter 5 describes how engineering the cladding structure of photonic crystal �bres can be used to generate shorter frequencies in supercontinuum generation. The method by which this achieved is experimentally veri�ed and then exploited to generate a continuum incorporating the entire visible spectrum using low cost, low maintenance pump sources.

Date of Award	1 Apr 2009
Original language	English
Awarding Institution	University of Bath
Supervisor	Jonathan Knight (Supervisor)