Fiber laser refers to the laser using rare earth doped glass fiber as the gain medium. Fiber laser can be developed on the basis of fiber amplifier: under the action of pump light, high power density is easily formed in the fiber, causing the "particle number inversion" of the laser working material. When a positive feedback loop (forming a resonant cavity) is properly added, the laser oscillation output can be formed.

The application scope of fiber laser is very wide, including laser fiber communication, laser space long-distance communication, industrial shipbuilding, automobile manufacturing, laser engraving, laser marking, laser cutting, printing roll, metal non-metallic drilling/cutting/welding (brazing, quenching, cladding and deep welding), medical equipment and equipment, large-scale infrastructure, as the pump source of other lasers, etc.

Structure of fiber laser

The generation of laser signal requires three basic conditions: particle number inversion, optical feedback and reaching laser threshold. Therefore, the laser is composed of three parts: working material, pump source and resonant cavity. The basic structure of the fiber laser is as follows: the gain fiber is the gain medium that generates photons; The role of the pump light is as an external energy to make the gain medium achieve the particle number inversion, that is, the pump source; The optical resonator consists of two mirrors, which are used to feedback photons and amplify them in the working medium. The pump light is absorbed after entering the gain fiber, which makes the number of energy level particles in the gain medium reverse. When the gain in the resonant cavity is higher than the loss, laser oscillation will be formed between the two mirrors, generating laser signal output.