The high-power fiber laser technology is currently one of the rapidly advancing laser technologies, primarily due to its outstanding performance in various fields, such as communication, research, industry, and defense.

Based on the development trend of the laser technology, the Shanghai Institute of Optics and Fine Mechanics (SIOM) took the lead in researching the fiber laser technology in China and decided that two key technologies are the high-power narrow line-width fiber laser technology and high-power fiber laser beam combining technology. Based on the optical fiber-based laser properties, the narrow-line-width fiber laser output power must be increased to suppress different nonlinear effects. This increase depends on the single frequency seed spectrum modulation combined with the multistage power amplifier technology, which can maintain the spectrum width and realize beam quality during the single-fiber laser power amplification process. For high-power fiber laser beam combining, SIOM first proposed and studied the all-fiber ring cavity coherent beam combining technology and spectral beam combining technology in China. This paper reviews the progress in recent years. SIOM has overcome a series of technical difficulties and achieved a series of achievements, which has driven the promotion and development of these technologies.

In the future, the narrow-line-width fiber laser technology can be used as an effective light source for the development of fiber lasers and beam combining technology. The main problem of nonlinear width fiber laser continues to be nonlinear effects: SBS and TMI. However, these may be improved via three aspects: using the new optical fiber material technology, new spectral modulation technology, and polarized high-power narrow-line-width fiber laser technology. The future demand for higher power and excellent beam quality is expected to be the comprehensive application of different beam combining technologies, complementing each other. Of course, suppressing the nonlinear effect of the laser, developing high-performance devices, and combining cavity structure optimization and beam quality maintenance technology are the basis of the development of the high-energy fiber laser technology. At present, the narrow-line-width fiber laser combined with the laser beam combining technology is the preferred solution of the high-energy light source.