I. What is a fiber laser

Fiber laser refers to a laser that uses rare earth-doped glass fiber as a gain medium. Fiber lasers can be developed on the basis of fiber amplifiers: under the action of pump light, it is easy to form high power density in the optical fiber. , causing the laser energy level of the laser working material to "invert the number of particles". When the positive feedback loop (forming a resonant cavity) is appropriately increased, laser oscillation output can be formed.

The application range of fiber lasers is very wide, including laser fiber communication, laser space communication, industrial shipbuilding, automobile manufacturing, laser engraving, laser marking, laser cutting, printing rollers, metal and non-metal drilling/cutting/welding (copper welding, quenching, cladding and deep welding), military defense and security, medical equipment and equipment, large-scale infrastructure, as a pump source for other lasers, etc.

II. What are the types of fiber lasers

(1) Classification by fiber material type

1. Crystal fiber laser. The working material is laser crystal fiber, mainly ruby ​​single crystal fiber laser and Nd3+:YAG single crystal fiber laser.

2. Nonlinear fiber laser. Mainly stimulated Raman scattering fiber laser and stimulated Brillouin scattering fiber laser.

3. Rare earth doped fiber laser. The matrix material of the optical fiber is glass. Rare earth element ions are doped into the optical fiber to activate it and make a fiber laser.

4. Plastic fiber laser. Fiber lasers are made by doping laser dyes in the core or cladding of plastic optical fibers.

(2) Classification by gain medium

1. Crystal fiber laser. The working material is laser crystal fiber, mainly ruby ​​single crystal fiber laser and Nd3+:YAG single crystal fiber laser.

2. Nonlinear fiber laser. Mainly stimulated Raman scattering fiber laser and stimulated Brillouin scattering fiber laser.

3. Rare earth doped fiber laser. Rare earth element ions are doped into the optical fiber to activate it (Nd3+, Er3+, Yb3+, Tm3+, etc., the matrix can be quartz glass, zirconium fluoride glass, single crystal) to make a fiber laser.

4. Plastic fiber laser. Fiber lasers are made by doping laser dyes in the core or cladding of plastic optical fiber.

(3) Classification by cavity structure

It is divided into F-P cavity, ring cavity, ring reflector fiber resonator and “8” type fiber resonator. shaped cavity, DBR fiber laser, DFB fiber laser, etc.

(4) Classification by fiber structure

It is divided into single cladding fiber laser, double cladding fiber laser, photonic crystal fiber laser and special fiber laser.

（5）Classification by output laser characteristics

It is divided into continuous fiber lasers and pulsed fiber lasers, among which pulsed fiber lasers can be divided into Q-switched fiber lasers (pulse width is in the order of ns) and mode-locked fiber lasers (pulse width is in the order of ps or fs) according to their pulse formation principle. amplitude).