Applications of light propagation in novel photonic devices

In this thesis, the propagation of light in novel photonic devices has been studied theoretically, numerically and experimentally. In particular, self-similar solutions to the nonlinear Schrödinger equation have been investigated as a means of avoiding distortions associated with high power pulse propagation in optical fibres. The results show that it is the interplay between the nonlinear and dispersive effects that leads to stable formation of the self-similar solutions. By considering generalised nonlinear Schrödinger equations we have extended the previous investigations of linearly chirped parabolic pulse solutions, which exist in the normal dispersion regime, and have found a new broader class of self-similar solutions, which exist when the fibre parameters are allowed to vary longitudinally. Numerical simulations of these systems confirm the analytic predictions. Experimental confirmation of parabolic pulse generation in high gain cascaded amplifier systems and in highly nonlinear microstructured fibres is also reported. In addition, the propagation of light in modulated crystal structures has been investigated. By modifying the linear and nonlinear properties of the crystals it has been shown that it is possible to manipulate the speed and the wavelength of the propagating light. In particular, negative refractive index materials have been shown to support fast and/or slow propagating light, whilst two dimensional nonlinear photonic crystals have been used to demonstrate multiple harmonic generation over a wide range of phase matching angles. The influence of waveguiding geometries has also been considered to determine the optimum design for the efficiency of the devices