Dual-wavelength quasi-mode-locked regimes of an Er-doped fiber ring laser

We demonstrate the dual-wavelength quasi mode-locked operation of a passively mode-locked Er-doped fiber ring laser with twisted fiber in the cavity and a double-pass amplifier with a Faraday mirror. The configuration allows very strict control of the polarization. We observed synchronous dual-wavelength generation of noise-like pulses (NLP) with spectra centered at 1534 nm and 1562 nm. Rotation of the azimuth of the radiation propagating in the cavity caused a switching between the generation of NLPs and packets of pulses with typical solitons spectrum. In the latter regime, we observed partially synchronous sub-pulses at two different wavelengths.