We have proposed and demonstrated a multiwavelength fiber laser based on nonlinear polarization rotation (NPR). The mechanism for stable room-temperature multiwavelength operation contributes to the ability of the intensity-dependent loss in NPR to effectively alleviate mode competition. In addition, through tuning the birefringence fiber filter, the lasing wavelength can be accurately tuned in the free spectrum range of the in-line periodic filter.
Zhang, Z., Zhan, L., Xu, K., Wu, J., Xia, Y., & Lin, J. (2008). Multiwavelength fiber laser with fine adjustment, based on nonlinear polarization rotation and birefringence fiber filter. Optics Letters, 33(4), 324-326. https://doi.org/10.1364/OL.33.000324