We report a passive mode-locked fiber laser (PMLFL) in a novel configuration to generate a single soliton with ultra-low repetition rate. The configuration includes a Faraday mirror after the first half of the cavity length to counteract the nonlinear polarization rotation effects. The total cavity length is 428 m including a 400-m SMF-28 fiber which was twisted to cancel the linear birefringence. The strict polarization control establishes a relation between the regimes of generation and the polarization state of the pulses propagating in the cavity. By properly adjusting the initial polarization state, we observed three different emission regimes, the single soliton regime (SR), conventional noise-like pulses (NLP) and noise-like square-waveform pulse (NLSWP). In the SR, we obtain a 2.9 ps pulse duration centered at 1558.7 nm with a 467.2 kHz repetition rate.
We report dual-wavelength mode-locked operation of a passively mode-locked Er-doped fiber laser (EDFL) including two sections of a fiber with equal length, one right hand twisted and another left hand twisted, and a double-pass amplifier with Faraday Mirror (FM). The configuration allows cancellation of the influence of both linear and circular birefringence and strict control of the polarization of pulses in the cavity. Depending on the polarization azimuth we observed synchronous dual-wavelength, 1532 nm and 1560 nm, noise-like pulses (NLP), and desynchronized soliton emission.
We report the dynamics of multi-pulse in a ring cavity passively mode-locked fiber laser with a strict control of the polarization state. We study the relation between the polarization state of the pulses propagating in the cavity and the regimes of generation. We have found that small ellipticities, the laser generates one bunch of pulses in the cavity, while at higher ellipticities the laser generates multiple bunches. At constant ellipticity we rotated the polarization azimuth and observed a regime transition from the generation of a bunch of solitons to that of noise-like pulses (NLP).