Influences of gain broadening on multiwavelength oscillations in YDFLs and EDFLs

We report the comparisons of the influences of gain broadening on multiwavelength oscillations in YDFL and EDFL with typical commercial ytterbium- and erbium-doped Al/Ge silica fibers. Our experimental results show that both the YDF and the EDF exhibit inhomogeneous gain broadening, which allows the lasing lines to increase with the increase of the pump, however, multiwavelength oscillations of the EDFL are more stable than those of the YDFL, in particular, when the wavelength spacing is small. Moreover, the minimum wavelength spacing for stable multiwavelength operations of the YDFL and the EDFL are observed to be 1.0 and 0.8 nm at room temperature, and 0.8 and 0.25 nm at 77 K, respectively. This show that the inhomogeneous gain broadening of the EDF may be stronger than that of the YDF.