Mode-Locked Soliton Fiber Laser Using an Intracavity Polarization Maintaining Photonics Crystal Fiber

A passively mode-locked soliton fiber laser assisted with an interference filter is proposed and experimentally demonstrated. Self-started mode-locked soliton generation is based on the nonlinear polarization evolution (NPE). Of which, a polarization maintaining photonics crystal fiber (PM-PCF) is incorporated as an interference filter with tunable transmission bandwidth by controlling length of PM-PCF. In the experiment, we achieve a clean spectrum of dissipative soliton (DS) without sidebands, and a corresponding repetition rate of 6.554 MHz. Further adjusting the intracavity polarization with two polarization controllers (PCs) can transform the conventional DS to a vector DS with a rectangular spectrum. It is seen that the soliton operation regime can be dynamically managed by controlling the intracavity polarizations and net birefringence.