Low threshold multi-wavelength erbium-doped fiber ring laser with NOLM and Lyot filter.

• We propose a low threshold multi-wavelength erbium-doped fiber ring laser with NOLM and Lyot filter. • The threshold pump power of the laser is 45 mW, and can get 12 stable lasing lines, the side mode suppression ratio is greater than 25 dB. • This laser's channel spacing can be changed among of 0.08 nm, 0.34 nm and 0.89 nm by changing the PMF length. • This laser has simple structure and good stability. In this paper, the performance of a switchable multi-wavelength erbium-doped fiber laser (MWEDFL) incorporating Lyot filter and nonlinear optical loop mirror (NOLM) is described. The NOLM consisting of a polarization controller (PC2) and a single-mode fiber is effective to suppress the mode competition caused by the homogeneous broaden line in the erbium-doped fiber amplifier (EDFA). The comb filter is developed by using PC1 and polarization-maintained fiber (PMF). The wavelength interval can be switched among 0.08 nm, 0.34 nm, and 0.89 nm using different lengths of PMF via careful adjusting of the PCs. When the pump power is 45mW, the laser can emit 12 stable lasing lines within the 3 dB bandwidth, and the side mode suppression ratio (SMSR) is greater than 25 dB. The spectral power and wavelength fluctuations of 1.9 dB and 0.16 nm, respectively. Experimental results reveal that the demonstrated laser has good stability and low threshold power. [ABSTRACT FROM AUTHOR]