Experimental and numerical evaluation of freely spacing-tunable multiwavelength fiber laser based on two seeding light signals

A model of multiwavelength erbium-doped fiber laser (MEFL), which takes into account the impact of fiber attenuation on the four-wave-mixing (FWM), is proposed. Using this model, we numerically study the output characteristics of the MEFL based on FWM in a dispersion shift fiber with two seeding light signals (TSLS) and experimentally verify these characteristics. The numerical and experimental results show that the number of output channels can be increased with the increase of the erbium-doped fiber pump power. In addition, by decreasing the spacing of TSLS and increasing the power of TSLS, the number of output channels can be increased. However, when the power of TSLS exceeds a critical value, the number of output channels decreases. The results by numerical simulation are consistent with experimental observations from the MEFL.