Recent progress of high-power single-frequency all-fiber oscillators and amplifiers

High-power single-frequency fiber lasers have attracted great attention in the applications of high-resolution spectroscopy, long-distance coherent communication, gravitational wave detection and some other areas, due to the advantage on narrow linewidth, low noise and so on. In this paper, we systematically summarize the recent achievements of high-power singlefrequency fiber laser oscillators and amplifiers as well as performance improvement on noise suppression, linewidth narrowing, and wavelength extension. Besides, the next development of SFFLs has been prospected.