Tunable Multiwavelength Passively Mode-Locked Fiber Ring Laser Using Intracavity Birefringence-Induced Comb Filter

Abstract

A simple configuration for the generation of tunable multiwavelength picosecond-pulse fiber ring lasers by exploiting the intracavity birefringence-induced comb filter is demonstrated. The fiber laser is passively mode locked by using nonlinear polarization rotation (NPR) technique. The polarization-dependent isolator combined with the intracavity birefringence acts as two functions: the tunable comb filter and the mode locker. Up to four-wavelength picosecond pulses were simultaneously obtained in the experiment. The mode competition of the multiwavelength lasing is suppressed by the use of NPR-induced intensity-dependent loss. In addition, the number of the lasing wavelengths, the lasing location, and the spacing between the lasing wavelengths could be flexibly tuned by properly rotating the polarization controllers.

Keywords

• Multiwavelength lasers
• passively mode-locked
• fiber lasers
• birefringence filter