Investigation of a multiwavelength thulium-doped fiber laser incorporating a two-mode fiber filter

摘要

A multiwavelength, thulium-doped, ring fiber laser was proposed and experimentally demonstrated. The laser was realized exploiting the cooperative effects of a two-mode fiber filter, nonlinear polarization rotation and the four-wave mixing induced by a section of a highly nonlinear fiber with a length of 150 m. By fine-tuning the polarization controllers, stable multiwavelength outputs with 11 lasing lines within the bandwidth of 10 dB were obtained in 60 min. The maximum wavelength shift and optical power fluctuation of the eleven-wavelength operation for the laser are 0.08 nm and 1.86 dB, respectively, and the wavelength interval and the number of lasing lines can be changed by adjusting the length of the two-mode fiber. Furthermore, the effects of the different experimental parameters such as the pump power, output coupling ratio, nonlinear phase shift and the extinction ratio of the filter on the output performance have also been carefully investigated.