Wavelength-number-tunable multi-wavelength SOA fiber laser based on NPR effect

A wavelength-number-tunable multi-wavelength SOA fiber laser incorporating a double pass Mach-Zehnder interferometer (MZI) is experimentally demonstrated in this paper. Due to the nonlinear polarization rotation (NPR) effect of SOA, the intensity-dependent loss (IDL) is induced by the combination consisting of SOA and polarization devices to achieve stable multiwavelength output with ultra-narrow wavelength spacing. In addition, the degree of IDL can be controlled by adjusting PCs for the purpose of tuning the number of wavelengths. Stable multiwavelength output with power equality have been achieved at room temperature, which have no obvious power fluctuation. The wavelength spacing is ultra-narrow, which is as small as 0.081 nm, and the number of lasing lines is tuned from 168 to 250. However, due to the high noise figure of SOA, the optical signalto-noise ratios (OSNR) is less than 8.85 dB.