Since the last decade, the development of ultrafast laser technology have led to various new and fascinating application in scientific research, industry and medicine. This is due to the great feature of the laser that produce superior performance. Since the discovery of laser action in Ti:sapphire in 1982, Ti:sapphire becomes one of the most popular solid-state laser material for ultrafast laser system. It combines the excellent thermal, physical and optical properties of sapphire with the broadest tunable range of crystal based laser material. The output spectrum cover the entire band from 660 to 1100 nm.This book explains the basics knowledge of the ultrafast laser and the Ti:sapphire laser oscillator construction for femtosecond pulse laser generation.