A Narrow-Linewidth Holmium Fiber Laser with Random Distributed Feedback Based on Artificial Rayleigh Backscattering.

The results of development and investigation of the characteristics of a holmium fiber laser generating at the wavelength of 2 μm in cavity configurations with distributed Bragg reflectors (DBRs) and with random distributed feedback (RDFB) provided by artificial Rayleigh reflectors are considered. The length of the active medium was 75 cm. For the linear scheme with DBRs, the output power was about 330 mW at a pump power of 3.9 W, while the linewidth did not exceed 10 pm. For the configuration with RDFB, the maximum output power was 360 mW, and the generation linewidth was about 3 pm, while up to the output power level of 90 mW, a single-frequency generation regime was observed and the temporal dynamics was pulsed. [ABSTRACT FROM AUTHOR]