Abstract This letter compares the optical spectra of holmium- and thulium-doped silica fiber lasers operating in the continuous-wave regime with an output power of about 10 W. The lasers are based on commercial gain fibers placed into a Fabry–Perot cavity, in which one or two commercial high-power fiber Bragg gratings are used as in-fiber selective mirrors. The evolution of the lasers’ spectra with increasing laser power, including variations in the laser wavelength and spectrum width, is discussed.
Barmenkov et al. (Thu,) studied this question.