Active Control of Rogue Waves for Stimulated Supercontinuum Generation

We demonstrate that rogue waves provide a powerful tool to actively control a nonlinear system with minimal effort. Specifically, optical rogue waves—rare, bright flashes of broadband light arising in subthreshold supercontinuum generation—are initiated by an exceedingly weak stimulus. Using this effect, we produce an optically switchable, ultrastable, and bright supercontinuum with greatly enhanced coherence.

Figure 1

(a) Illustration of the impact of a weak stimulus on the input pulse. With proper timing and frequency, SC is produced (bottom), whereas SC is not generated otherwise (top). (b),(c) Measured spectra without and with the proper stimulus, respectively, at the indicated power levels. Small arrows indicate soliton shedding from the MI wing, clearly discernible when the stimulation is present.

Figure 2

(a) Measured (filtered) SC power with and without the seed. (b) Measured (filtered) SC pulse-to-pulse intensity statistics with (green) and without (blue) the stimulus ($\sim 100$ events each). Pump power is adjusted ($P_{\mathrm{pump}}\approx 130\mathrm{W}$ stimulated, $\approx 200\mathrm{W}$ spontaneous) to keep average SC output power constant. Inset illustrates segments of the filtered SC pulse train for different seed delay. Negative time corresponds to advanced seed. (c) Measured spectral interferograms of a coherently stimulated SC (green trace) and a conventional, spontaneous SC (blue trace). Fringes are visible only for the seeded SC.

Figure 3

SC power integrated over redshifted wavelengths ($>1680\mathrm{nm}$) as a function of the time delay and frequency shift of the seed pulse for intensities: (a) 0.01% and (b) 0.001% of pump. Negative time corresponds to the pump’s leading edge. $P_{\mathrm{pump}}=130\mathrm{W}$, ${\tau }_{\mathrm{pump}}=3.7\mathrm{ps}$, ${\tau }_{\mathrm{seed}}=200\mathrm{fs}$.

Figure 4

(a) Complex-plane scatter plot of the SC electric field amplitude ($\lambda =1950\mathrm{nm}$, $\Delta \lambda =5\mathrm{nm}$) from many independent events: 130 W pump peak power, stimulated (green, tightly clustered on dotted circumference); 255 W, spontaneous (blue, scattered). Although SC average power is comparable for both cases, fluctuations are nearly eliminated with seeding (magnitude, $CV=0.036\%$; phase, $\sigma =23\mathrm{mrad}$). (b) Single-shot stimulated (green) and spontaneous (blue) relative power spectral densities from 130 W pump. (c) Filtered ($>1680\mathrm{nm}$) SC power with (green squares) and without (blue circles) seeding.