A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation in photonic crystal fiber

The Peregrine soliton — a wave localized in both space and time — is now observed experimentally for the first time by using femtosecond pulses in an optical fibre. The results give some insight into freak waves that can appear out of nowhere before simply disappearing.

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The Peregrine soliton in nonlinear fibre optics

Numerical simulations of the onset phase of continuous wave supercontinuum generation from modulation instability show that the structure of the field as it develops can be interpreted in terms of the properties of Akhmediev Breathers. Numerical and analytical results are compared with experimental measurements of spectral broadening in photonic crystal fiber using nanosecond pulses.

/pdf/modulation-instability-akhmediev-breathers-and-continuous-3vcrfffvha.pdf

Modulation instability, Akhmediev Breathers and continuous wave supercontinuum generation.

Supercontinuum generation, photonic crystal fiber

The Akhmediev breather formalism of modulation instability is extended to describe the spectral dynamics of induced multiple sideband generation from a modulated continuous wave field. Exact theoretical results describing the frequency domain evolution are compared with experiments performed using single mode fiber around 1550 nm. The spectral theory is shown to reproduce the depletion dynamics of an injected modulated continuous wave pump and to describe the Fermi–Pasta–Ulam recurrence and recovery towards the initial state. Realistic simulations including higher-order dispersion, loss, and Raman scattering are used to identify that the primary physical factors that preclude perfect recurrence are related to imperfect initial conditions.

/pdf/spectral-dynamics-of-modulation-instability-described-using-425o878n8h.pdf

Spectral dynamics of modulation instability described using Akhmediev breather theory

Dynamical evolution of multiple four-wave-mixing processes in an optical fiber

When two optical waves at frequencies ${\mathrm{\ensuremath{\omega}}}_{1}$ and ${\mathrm{\ensuremath{\omega}}}_{2}$ interact in a medium with cubic nonlinearity, multiple four-wave-mixing processes can generate pairs of sidebands. A conservation law that connects the amplitudes of the pump waves and sidebands is shown to arise from the Manley-Rowe relations and from the infinite set of conservation relations of the nonlinear Schr\"odinger equation. The conservation relation is examined theoretically and verified experimentally for a variety of input pump power levels and asymmetries. It can be used as a diagnostic measure to determine if nonlinearities of higher order than cubic are present.

D. L. Hart

Papers

Dynamical evolution of multiple four-wave-mixing processes in an optical fiber

Conservation law for multiple four-wave-mixing processes in a nonlinear optical medium