The inherent features of nonlinear optics is the modification of the optical properties of the medium due to the interaction of the propagating high intensity light with the medium ultimately leading to the generation of new frequencies. An ultra-short pulse experiences spectral broadening when it is passed through a nonlinear medium such as high purity silica fibre and eventually generates artificial white light with unique spectral properties, controlled time duration and high spectral brightness. Owing to its wide and continuous spectra, such phenomenon is generally called supercontinuum (SC) generation. A variety of nonlinear processes governed by the associated pulse duration are involved in such spectra broadening. For femtosecond pump pulses, solution dynamics plays a pivotal role whereas self-phase modulation (SPM), four wave mixing (FWM) etc are important for wider pump pulses. The generation of white light is an interesting physical phenomenon and it opens up new possibilities in the field of optical communication, optical metrology, nonlinear spectroscopy, microscopy and laser biomedicine. In this review, particular attention is paid to the description of the formation of white light in different operational conditions in highly nonlinar waveguides such as photonic crystal fibre (PCF).
