Laser cutting technology is an important application of laser technology in industry. It has become the most laser processing method in the current industrial field, accounting for more than 70% of the whole laser processing.Laser cutting has been widely used in modern industry due to its advantages such as wide cutting range, high cutting speed, narrow slit, good cutting quality, small heat-affected area and large processing flexibility, and it has also become one of the most mature technologies in laser processing technology. 

   There are many kinds of lasers used in laser processing, and new lasers are being developed constantly.At present, CO2 laser, YAG laser, excimer laser, high-power semiconductor laser and fiber laser are mainly used in laser processing and manufacturing.Among them, high power CO2 laser and YAG laser are widely used in large workpiece laser processing technology.Small and medium power CO2 laser and YAG laser are widely used in precision machining.Excimer lasers are mostly used in micromachining, and because ultrashort pulsed lasers can inject energy into the irradiation site more quickly than thermal diffusion of materials, they are mainly used in ultra-fine laser machining.The semiconductor laser is the smallest laser volume and has been widely used in laser communication, laser storage, laser ranging and so on.Fiber laser based on fiber has obvious advantages in threshold reduction, oscillation wavelength range and tunable wavelength performance. It has become a new technology in laser field and one of many hot research topics.Like the traditional solid and gas laser, the fiber laser is composed of pump source, gain medium and resonator.The pump source is generally a high-power semiconductor laser, the gain medium is a rare earth doped fiber or a common nonlinear fiber, and the resonator can be composed of a variety of linear resonators by optical feedback elements such as fiber gratings, or a variety of ring resonators by couplers.The pump light is coupled into the gain fiber by an appropriate optical system. After absorbing the pump light, the gain fiber generates the particle number inversion or the nonlinear gain generates the spontaneous radiation.After the excitation amplification and the mode selection of the resonator, the generated spontaneous radiation finally forms a stable laser output.