**High‐Energy and Short‐Pulse Generation from Passively Mode‐Locked Ytterbium‐Doped Double‐Clad Fiber Lasers**

Yuzhai Pan

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/63900

#### **Abstract**

Mode‐locked ytterbium‐doped fiber lasers capable of producing nanosecond‐, picosecond‐ or femtosecond‐level pulses with high energy or power have many advantages for various applications such as material processing and laser surgery. Firstly, in this chapter, the principles and methods used in passively mode‐locked fiber lasers are briefly described. Secondly, mathematical modeling of all normal disper‐ sion ytterbium‐doped fiber lasers for analyzing the pulse generation and propagation has been established and simulated with the generalized nonlinear Schrödinger equation. Thirdly, short pulses generated from passively mode‐locked fiber lasers have been demonstrated with carbon nanotube– deposited D‐shaped fiber as the saturable absorber. Different pulse width can be realized with different parameters of the laser cavity. Finally, the main amplification methods for short laser pulses have been discussed, and a broad prospect for applications of various technologies using short‐ pulse fiber lasers is further introduced.

**Keywords:** Ultra-short pulse, passively mode‐locked fiber laser, carbon nanotube sat‐ urable absorber, double‐clad ytterbium‐doped fiber
