Wavelength-Tunable Rectangular Pulse Dissipative Soliton Operation of an Erbium-Doped Mode-Locked Fiber Laser

The wavelength-tunable rectangular pulse dissipative soliton (DS) is experimentally demonstrated, for the first time to the best of our knowledge, in an erbium-doped figure-of-eight fiber laser based on the nonlinear amplifying loop mirror mode-locked technique. The proposed rectangular pulse DS fiber laser can operate in the wavelength-tunable mode-locked state from 1573.5 nm to 1594.6 nm with the rotation of the polarization controllers. The achieved output wavelengths are 1573.5 nm, 1576.3 nm, 1586.8 nm, 1590.4 nm and 1594.6 nm, respectively. The pulse widths of the rectangular pulse can also be tuned from ～8 ns to ～24 ns by adjusting the pump power. The fundamental repetition rate of the rectangular pulse DS is 1.154 MHz and the output power is 6.14 mW (at 1594.6 nm).