This book presents a study of nonlinear optical phenomena with ultra-broadband radiation and ultrashort pulses in photonic crystal fiber (PCF) using numerical modeling. For the description of these processes, two widely used techniques namely pulse compression and soliton induced supercontinuum generation are implemented. Hence, the goal of the book can be divided into two topics namely pulse compression and supercontinuum generation which are connected to each other by the investigation of ultrasort pulses and broadband spectrum in PCF. To analyse the pulse compression and supercontinuum process in PCF, several numerical and theoretical approaches such as fully vectorial effective index method, finite element method, projection operator method, split step Fourier method, modulational instability technique and self-similar analysis has been utilized.