Mechanism of intrinsic wavelength tuning and sideband asymmetry in a passively mode-locked soliton fiber ring laser

We have experimentally observed continuous-wavelength tuning in a passively mode-locked fiber ring laser. Depending on the polarization setting, two separated tuning ranges are observed. We show that the wavelength tuning is a result of the existence of birefringence in the laser cavity. We have also shown that the same mechanism is responsible for the power asymmetry of sidebands appearing in the soliton spectrum.