Study On Acousto - Optic Q - Doped Nd ^{3 +} Double - Clad Fiber

Q-switched fiber laser compared with the normal Q-solid-state lasers has advantages of high beam quality, good heat dissipation and small size, etc. In addition, Q-switched fiber lasers are widely used in the fields of space exploration, remote sensing, optical time domain reflectometer and so on. Besides short pulse of1.06μm is easily absorbed by metals, plastics and ceramics, so focusing it onto the surface of medium, use the laser beam interact with the material to change the physical properties of the material.It can be used in laser-processed. This paper is based on the theoretical simulation, mainly through the experimental method to obtain laser output of1.06μm Q-switched laser.This paper firstly introduces the theoretical basis of Q-switched fiber laser, then we numerical simulation of how doped fiber length and pump power infect the laser operating characteristics, according to Nd3+ions rate equations. Simulation results show that:t there exists an optimum fiber length can allow1.06μm fiber laser to get the highest output power, and the output power increases with the increase of pump power.Based on the theoretical modeling, we studied the Acousto-optic Q-switched Nd3+-doped double-clad fiber lasers. Its center wavelength is1.06μm. This experiment is consists of two parts. Part I is used to obtain a stable1.06μm CW laser output. Its resonator is consists of two FBGs, the gain medium is15m long Nd3+-doped double-clad fiber. We use fiber end fused coupling as the coupled manner, and finally get3.6W output power when the pump current is22A, the spectrum line width is3nm. In the second part we weld the fiber coupled acousto-optic Q switched laser into the laser resonant cavity. We periodic control the diffraction of laser resonant cavity through the AOM Q-switch. The pulse width of the laser is28ns, pulse peak power is34.7kW, when the pump power is10A, the repetition frequency is2.8kHz.