Kompetenzzentrum für optische Spezialfasern

The emission of resonant radiation from temporal solitary waves—also known as dispersive wave generation—allows efficient energy transfer to far-distant spectral domains. This coherent radiation can deliver large spectral densities at selected wavelengths once control over the individual soliton is achieved. Here, the concepts of few-mode operation and local temperature tuning are combined for precise steering of cascaded dispersive wave generation in liquid-core optical fibers. By exciting higher-order TM and TE modes with femtosecond pulses at 1600 nm, the generation of two dispersive waves tunable by up to 33 nm K−1 through adjusting a selected part of the waveguide is observed. Sophisticated soliton-driven nonlinear dynamics arising from thermally transitioning from anomalous to all-normal dispersion with temperature changes of only a few Kelvin have been found, including soliton steering, soliton breakdown, and soliton post-fission tuning. All experimental results are verified by nonlinear simulations and semi-analytic phase-matching calculations, overall providing a cost-effective and practical toolbox for discovering unexplored states of light as well as for developing dynamically tunable broadband light sources.