Optical Supercontinuum Generation Research Articles

Controlling formation and suppression of fiber-optical rogue waves.

Fiber-optical rogue waves appear as rare but extreme events during optical supercontinuum generation in photonic crystal fibers. This process is typically initiated by the decay of a high-order fundamental soliton into fundamental solitons. Collisions between these solitons as well as with dispersive radiation affect the soliton trajectory in frequency and time upon further propagation. Launching an additional dispersive wave at carefully chosen delay and wavelength enables statistical manipulation of the soliton trajectory in such a way that the probability of rogue wave formation is either enhanced or reduced. To enable efficient control, parameters of the dispersive wave have to be chosen to allow trapping of dispersive radiation in the nonlinear index depression created by the soliton. Under certain conditions, direct manipulation of soliton properties is possible by the dispersive wave. In other more complex scenarios, control is possible via increasing or decreasing the number of intersoliton collisions. The control mechanism reaches a remarkable efficiency, enabling control of relatively large soliton energies. This scenario appears promising for highly dynamic all-optical control of supercontinua.

Rare frustration of optical supercontinuum generation

Recent work has shown that optical rogue waves, large bandwidth fluctuations following heavy-tailed statistics, can arise during spectral broadening by stochastic enhancement of nonlinearity. Here, we report the observation of a different form of extreme fluctuations in supercontinuum pulse trains: Pulses of unusually small spectral bandwidth following left-skewed heavy-tailed statistics. Displaying a pulse evolution strongly varying from that of large extremes in supercontinuum, these rogue events appear when spectral broadening is frustrated by competition between presolitonic features within the modulation-instability band. This suppression effect can also be externally induced with a weak control pulse.

Optical supercontinuum generation from nanosecond pump pulses in an irregularly microstructured air-silica optical fiber

An optical supercontinuum was generated by pumping a short length of randomly microstructured air-silica optical fiber with a Q-switched Nd:YAG laser. The use of relatively long pump pulses and a longer pump wavelength are believed to be responsible for an improvement in results relative to similar previous reports. A figure of merit for optical continuum generation is defined, and is shown to be considerably larger in this and other experiments in which stimulated Raman scattering, instead of self-phase modulation, is the primary nonlinear process seeding spectral broadening.