Power-dependent effective reflection of fiber Bragg grating as output coupler of Ytterbium-doped fiber laser

Ytterbium-Doped Fiber Laser as a Source of Coexisting Narrow-Band Thermal Light and Optical Rogue Waves: Experimental Demonstration

“…[1][2][3][4][5][6]. CW double-clad (DC) YDFLs are very efficient light sources with optical-tooptical conversion efficiency as high as 80% [1,7,8] and a wide optical range, from ~ 975 nm to ~ 1180 nm [9][10][11][12][13][14], with output power scalable up to very high levels, from several kW in single mode [7,8,15] to tens of kW in multi-mode configurations [16][17][18]. Due to very large power scaling and the perfect energy budget YDFLs found a great number of biomedical [19,20] and industrial applications [21], they can be used as an optical pump for other types of lasers [22][23][24][25], for frequency nonlinear conversion [26,27], and so on.…”

“…If the intra-cavity laser power is high enough so that the optical nonlinear effects related to the Kerr nonlinearity play an important role in the laser wave evolution, the laser optical spectrum dramatically broadens [13,31]. This effect leads to a decrease in the effective reflection of the laser output coupler (low reflection FBG) due to a spectral surrounding of its reflection spectrum by the laser wave with a broadened spectrum and, consequently, to decreasing the quality factor of the laser cavity and to increasing the active fiber gain [13]. In turn, the latter may result in arising CW parasite lasing at the wavelength at potentially dangerous for the active fiber [32].…”