According to the type of fiber material, fiber lasers can be divided into:

1. Crystal fiber laser. The working substance is a laser crystal fiber, mainly including a ruby ​​single crystal fiber laser and a nd3+:YAG single crystal fiber laser.

2. Nonlinear optical fiber lasers. There are mainly stimulated Raman scattering fiber lasers and stimulated Brillouin scattering fiber lasers.

3. Rare earth doped fiber lasers. The matrix material of the optical fiber is glass, which is activated by doping rare earth element ions into the optical fiber to form a fiber laser.

4. Plastic fiber laser. A fiber laser is prepared by incorporating a laser dye into a core or cladding of a plastic optical fiber.

Classified by gain medium as:

a) Crystal fiber laser. The working substance is a laser crystal fiber, mainly including a ruby ​​single crystal fiber laser and a Nd3+:YAG single crystal fiber laser.

b) Nonlinear optical fiber lasers. There are mainly stimulated Raman scattering fiber lasers and stimulated Brillouin scattering fiber lasers.

c) Rare earth doped fiber lasers. The fiber is doped with a rare earth element ion to be activated, (Nd3+, Er3+, Yb3+, Tm3+, etc., the matrix may be quartz glass, zirconium fluoride glass, single crystal) to form a fiber laser.

d) Plastic fiber lasers. A fiber laser is prepared by incorporating a laser dye into a core or cladding of a plastic optical fiber.

(2) According to the cavity structure, it is classified into F-P cavity, annular cavity, loop reflector fiber cavity and "8" shaped cavity, DBR fiber laser, DFB fiber laser and so on.

(3) According to the fiber structure, it is classified into single-clad fiber laser, double-clad fiber laser, photonic crystal fiber laser, and special fiber laser.

(4) According to the output laser characteristics, it is classified into continuous fiber laser and pulsed fiber laser. Pulsed fiber laser can be divided into Q-switched fiber laser (with pulse width of ns) and mode-locked fiber laser (pulse width) according to its pulse forming principle. For ps or fs magnitude).

(5) According to the number of laser output wavelengths, it can be divided into single-wavelength fiber lasers and multi-wavelength fiber lasers.

(6) According to the tunable characteristics of the laser output wavelength, it can be divided into a tunable single-wavelength laser and a tunable multi-wavelength laser.

(7) According to the wavelength of the laser output wavelength, it is classified into S-band (1460~1530 nm), C-band (1530~1565 nm), and L-band (1565~1610 nm).

(8) According to whether it is mode-locked, it can be divided into: continuous light laser and mode-locked laser. A typical multi-wavelength laser is a continuous optical laser.

According to the mode-locking device, it can be divided into a passive mode-locked laser and an active mode-locked laser.

Among them, passive mode-locked lasers have:

Equivalent/false saturated absorber: Nonlinear rotary mode-locked laser (8-shaped, NOLM and NPR)

True saturated absorber: SESAM or nanomaterials (carbon nanotubes, graphene, topological insulators, etc.).