All fiber tunable- or dual-wavelength Yb-doped fiber laser covering from dissipative soliton to dissipative soliton resonance

In this Letter, a simple and passively mode-locking Yb-doped all fiber laser using a nonlinear polarization rotation technique operating under dissipative soliton(DS) or dissipative soliton resonance(DSR) conditions is proposed, furthermore, using a combination of a bandpass filter and a Loyt filter, tunable single-wavelength or dual-wavelength operation under two different conditions is realized, respectively. The tunable single?wavelength DS laser has a 5 nm tuning range from 1029 to 1034 nm with a pulse width of 110 ps. The tunable single-wavelength DSR operation laser has a range of 4 nm. In-depth research on the mechanism of the con?version between DS and DSR is carried out. Particularly, under dual-wavelength DSR operation, the obtained step-like pulses consist of two rectangular pulses with different energies. This work could help give a deeper insight into normal dispersion pulses.