Bright and dark vector rogue waves

For an Erbium-doped mode locked fibre laser, we demonstrate experimentally a new type of vector rogue waves (RWs) emergence of which is caused by the coherent coupling of the orthogonal states of polarisation (SOPs). Unlike weak interaction between neighbouring dissipative solitons for the soliton rain, this creates a new type of the energy landscape where the interaction of the orthogonal SOPs leads to polarisation trapping or escapes from the trapping triggered by polarisation instabilities and so results in the pulse dynamics satisfying criteria of the 'dark' and 'bright' RWs. The obtained results, apart from the fundamental interest, can provide a base for development of the rogue waves mitigation techniques in the context of the applications in photonics and beyond.

Nonlinear distortion in mode delay compensated few-mode fibre spans with intermediate coupling

Nonlinear distortion in delay-compensated spans for intermediate coupling is studied for the first time. Coupling strengths under -30dB/100m allow distortion reduction using shorter compensation lengths and higher delays. For higher coupling strengths no significant penalty results from shorter compensation lengths.

Rogue waves generation via nonlinear soliton collision in multiple-soliton state of a mode-locked fiber laser

We report for the first time, rogue waves generation in a mode-locked fiber laser that worked in multiple-soliton state in which hundreds of solitons occupied the whole laser cavity. Using real-time spatio-temporal intensity dynamics measurements, it is unveiled that nonlinear soliton collision accounts for the formation of rogue waves in this laser state. The nature of interactions between solitons are also discussed. Our observation may suggest similar formation mechanisms of rogue waves in other systems.

Gravimetric and density profiling using the combination of surface acoustic waves and neutron reflectivity

A new approach is described herein, where neutron reflectivity measurements that probe changes in the density profile of thin films as they absorb material from the gas phase have been combined with a Love wave based gravimetric assay that measures the mass of absorbed material. This combination of techniques not only determines the spatial distribution of absorbed molecules, but also reveals the amount of void space within the thin film (a quantity that can be difficult to assess using neutron reflectivity measurements alone). The uptake of organic solvent vapours into spun cast films of polystyrene has been used as a model system with a view to this method having the potential for extension to the study of other systems. These could include, for example, humidity sensors, hydrogel swelling, biomolecule adsorption or transformations of electroactive and chemically reactive thin films. This is the first ever demonstration of combined neutron reflectivity and Love wave-based gravimetry and the experimental caveats, limitations and scope of the method are explored and discussed in detail.