The mysteries of monstrous waves in the oceans that appear and disappear without a trace dates back hundreds of years ago. Recent technological advances have enabled change these mysteries into scientific facts and phenomena. Presently, these extreme waves, popular by the name: rogue waves, have been a haven of much research as scientists have been attempting to understand and tame their disastrous and unpredictable nature that hamper human activities in the oceans. In the early stages of such studies, stochastic and large scaled research templates were mostly employed despite being expensive, time consuming and engaging bulky experimental setups. Consequently, rogue wave research platforms other than oceans were developed. These developments included optical configurations such as the optical-fiber-based super-continuum generation.
Currently, as an advancement from the latter, soliton-collision and soliton-focusing mechanisms have mainly been deemed responsible for the generation of rogue waves in dissipative fiber-optic systems. These systems are promising but the chaotic and random nature of rogue waves has rendered analysis nearly impossible. As a resolve, there is still need for extensive research, especially in the multi-soliton regime of passively mode-locked fiber lasers, that has yet to be investigated thoroughly as a rogue waves-generating platform.
To this note, a team of researchers led by Professor Yoonchan Jeong from the Laser Engineering and Applications Laboratory, Department of Electrical and Computer Engineering, Seoul National University in South Korea investigated the intermittent burst of a super rogue wave in the multi-soliton regime of an anomalous-dispersion fiber ring cavity. They hoped to exploit the spatio-temporal measurement technique to lock and capture the shot-to-shot wave dynamics of various pulse events in the cavity, and obtain the corresponding intensity probability density function. Their work is published in the research journal, Optics Express.
The researchers commenced their experimental work by laying out the passively mode-locked erbium-doped fiber lasers-based on nonlinear-polarization-rotation. They then used a total cavity length of ~ 120 m of a specific net cavity anomalous dispersion which was operated in the single-soliton regime for low power pump, and quasi-mode-locked regimes inclusive of the multi-soliton regime for higher pump power. Eventually, the researchers measured the cavity’s optical spectrum and spatio-temporal characteristics.
The authors observed that adjusting the cavity to hold a greater number of solitons drastically increased the natural probability of interactions among neighboring solitons, which, in turn, stimulated dispersive waves to take place. In addition, it was seen that by combining the probabilistically initiated soliton interactions and accompanying dispersive waves in their vicinity functioning as a catalyst, an avalanche of nonlinear interactions that evolved into super extreme events with even higher intensities emerged, hence the burst of a super rogue wave.
Yoonchan Jeong and colleagues study presented an excellent report on the extraordinary rogue waves intermittently triggered with an interval in the order of no longer than ten seconds in the multi-soliton regime of a nonlinear-polarization-rotation-mode-locked, anomalous-dispersion fiber ring cavity, for the first time. In this work, the researchers have experimentally observed and analyzed the intermittent burst of a super-rogue wave in the former conditions. To this end, their empirical work presented a novel and richer perspective that can be used as a stepping stone for the study of rogue waves, not only in the field of optics but also in other disciplines.
Seungjong Lee, Kyoungyoon Park, Hyuntai Kim, Luis Alonso Vazquez-Zuniga, Jinseob Kim, Yoonchan Jeong. Intermittent burst of a super rogue wave in the breathing multi-soliton regime of an anomalous fiber ring cavity. Volume 26, Number 9 | 30 Apr 2018 | Optics Express 11447.
Go To Optics Express