High-Power Multi-Wavelength Double-Clad Erbium Ytterbium Co-Doped Fiber Laser Using Two-and Four-Mode Fiber Filters

This work demonstrated a multiwavelength erbium-ytterbium co-doped double-clad fiber laser using two- (TMF) and four-mode fibers (FMF) as comb filters. At the maximum pump power of 9 W, the multi-wavelength fiber laser (MWFL) using the TMF filter generated 4 stable lasing lines with a spacing of 0.56 nm. The maximum output power recorded for this setup was as high as 553 mW with a 6.4% slope efficiency. Meanwhile, MWFL uses FMF filter generated 3 lasing lines with a spacing of 0.95 nm. The laser had a maximum output power of 443 mW with a slope efficiency of 5.3%. Both MWFLs were stable when operated for an extended period. The long-term stability test shows that the laser had only small wavelength drifts of 0.21 nm and 0.15 nm using the TMF and FMF filters, respectively. The maximum power fluctuations of the lasing lines were measured to be 2.10 dB for the MWFL using the TMF filter and 2.52 dB using the FMF filter. This work proposed stable high-power MWFL with higher output power and efficiency.