Polarization evolution dynamics of dissipative soliton fiber lasers

Abstract

Dissipative solitons emerge as stable pulse solutions of nonintegrable and nonconservative nonlinear physical systems, owing to a balance of nonlinearity, dispersion, and loss/gain. A considerable research effort has been dedicated to characterizing amplitude and phase evolutions in the spatiotemporal dynamics of dissipative solitons emerging from fiber lasers. Yet, the picture of the buildup process of dissipative solitons in fiber lasers is incomplete in the absence of corresponding information about the polarization evolution. Here, we characterize probabilistic polarization distributions in the buildup of dissipative solitons in a net-normal dispersion fiber laser system, mode-locked by single-wall carbon nanotubes. The output optical spectra under different pump powers are filtered by a tunable filter, and are detected by a polarization state analyzer. The laser system operates from random amplified spontaneous emission into a stable dissipative soliton state as the cavity gain is progressively increased. Correspondingly, the state of polarization of each spectral wavelength converges towards a fixed point. To reveal the invariant polarization relationship among the various wavelength components of the laser output field, the phase diagram of the ellipticity angle and the spherical orientation angle is introduced. We find that, within the central spectral region of the dissipative soliton, the state of polarization evolves with frequency by tracing a uniform arc on the Poincaré sphere, whereas in the edges of the dissipative soliton spectrum, the state of polarization abruptly changes its path. Increasing cavity gain leads to spectral broadening, accompanied by a random scattering of the state of polarization of newly generated frequencies. Further increases of pump power result in dissipative soliton explosions, accompanied by the emergence of a new type of optical polarization rogue waves. These experimental results provide a deeper insight into the transient dynamics of dissipative soliton fiber lasers.

Recent progress on optical rogue waves in fiber lasers: status, challenges, and perspectives

“…In other words, one can measure the optical spectrum of optical pulses in real time. Time-stretching methods have been widely employed in the experimental investigation of optical pulses in the fiber lasers by researchers, including the dissipative solitons, 52,129,130 soliton molecules, 131-133 chaotic pulses, 134,135 intermittent pulses, 78,136 transition dynamics, and other nonlinear dynamics. [137][138][139] In 2014, the Raman RW generation in the pulse fiber lasers was provided by the research group of Runge et al 82 By employing the pulse stretching method, the statistical histograms of wave events in more detail were investigated and the spectral evolution of RWs in real time was analyzed.…”

Broadband Dispersion-Managed Dissipative Soliton and Structural Soliton Molecules in a Slight-Normal Dispersion Fiber Laser

“…2(a). The spectrum exhibits quasi-rectangular profile, which is the typical feature for dissipative soliton in the normal dispersion regime [30]. Here, the 3 dB spectral bandwidth can be up to 56.5 nm and the central wavelength is about 1566 nm.…”

Fast and slow optical rogue waves in the fiber laser

“…Also, it has been found that optical RWs can be generated in mode-locked lasers due to the interaction of dissipative solitons through the overlapping of their tails or soliton-dispersive wave interactions [12,13]. An extensive study of the mechanisms of formation of optical RWs has been carried out either experimentally or theoretically in fiber lasers with nonlinearly driven cavities [14], Raman fiber amplifiers and lasers [15], random fiber lasers [16], and fiber lasers via modulation of the pump [17]. On the other hand, hopping between different attractors has also been investigated as a source of optical RW emergence [18,19].…”