Operating Principle and Characteristics of Fiber Laser Machine

Fiber laser machine is widely used in daily life. So, how does fiber laser machine work?

Ⅰ. Profile of fiber laser machine

Fiber laser machine is a mid-infrared laser with great development potential with optical fiber as the working material. According to its emission mechanism, it can be divided into rare-earth doped fiber laser machine, fiber nonlinear effect laser, single frequency fiber laser machine, fiber soliton laser, etc. Among them, the rare-earth-doped fiber laser machine has been very mature, such as erbium-doped fiber amplifiers have been widely used in optical fiber communication systems. High-power fiber laser machine is mainly used in military, laser processing, laser medical and other fields.

Ⅱ. Features of fiber laser machine

1. Fiber lasers are easy to achieve continuous operation at low pumping.

2. The fiber laser has a cylindrical structure, which is easy to couple with the fiber to realize various applications.

3. The radiation wavelength of the fiber laser is determined by the rare-earth dopant of the host material and is not controlled by the wavelength of the pump light. Therefore, the short-wavelength laser diode corresponding to the absorption spectrum of the rare-earth ion can be used as the pump source to obtain the mid-infrared band laser output.

4. The fiber laser is compatible with current fiber devices, such as modulators, couplers, polarizers, etc., so it can be made into an all-fiber system.

5. Fiber laser has simple structure, small size, simple and reliable operation and maintenance, and does not require complicated equipment such as water-cooled structure in semiconductor pumped solid-state laser system.

6. Compared with lamp-pumped lasers, fiber lasers consume only about 1% of the power of lamp-pumped laser systems, and the efficiency is more than twice that of semiconductor-pumped solid-state laser Nd:YAG.

7. Because fiber can only transmit basic spatial modes, the beam quality of fiber lasers is not affected by the operation of laser power, especially high-power double-clad fiber lasers have the advantages of high output power, large heat dissipation area, and good beam quality. And the output laser has a beam quality close to the diffraction limit.

Ⅲ. How does fiber laser work?

Taking rare-earth-doped fiber lasers as an example, a fiber core doped with rare-earth ions is used as a gain medium, and the doped fiber is fixed on two mirrors to form a resonant cavity. When the semiconductor pump laser passes through the optical fiber, the rare earth ions in the optical fiber absorb the pump light, and their electrons are excited to a higher laser energy level, realizing the particle inversion. The inverted particles transfer from a high energy level to a ground state in the form of radiation, and output laser light.