Propagation of Light Through Optical Fibre

This chapter presents the basic concepts on propagation of light through optical fibre. Propagation of light through a specific medium can be explained in two ways: geometric optics and wave theory. The chapter describes geometric optics to explain the guidance of light through the optical fibre and to calculate the transmitted optical power as a function of wavelength. It explains the wave theory by using a scalar model and vector model of a multilayer cylindrical optical fibre. The chapter discusses the most important factors of fibre losses: absorption, Rayleigh scattering, macrobending, and microbending. There are two main groups of microstructured optical fibre for the propagation of light: hollow core fibre (HCF) and photonic crystal fibre (PCF). In a PCF, light is transmitted through silica and in a HCF, light is transmitted through the air. The chapter also provides a discussion on propagation of light in specialty optical fibres focused on sensing.