Research progress on fiber laser spectral beam combining system and grating thermal analysis

The output power of single fiber is limited by the thermal effects, laser damage threshold, and nonlinear optical effects. Beam combining technology has been proposed to break through the limit of single fiber and achieve higher output power fiber laser. Spectral beam combining technology has the advantages of good beam quality and simple structure, which stands out among many beam combining technologies. We review several typical kinds of spectral beam combining technologies of fiber lasers, including their principles, current status, advantages and disadvantages. The recent progress of thermal distortion of the grating was introduced and discussed from the aspects of theoretical and experimental research, and the development trend of spectral beam combining technology are prospected.