Light: Sci. Applications 3, e131 (2014)

Dissipative solitons generated by mode-locked fibre lasers are attractive for metrology, high-resolution spectroscopy, optical fibre communications and nanophotonics applications. Now, Sergey Sergeyev and co-workers from Aston University in the UK have experimentally and theoretically investigated slowly evolving vector solitons measured over 25–25,000 round trips in an erbium-doped fibre laser that is mode locked with carbon nanotubes. Such solitons are characterized by a chaotic polarization attractor, which takes the form of a double scroll on the Poincaré sphere and has a correlation dimensionality of about 1.6. The team developed a model that, unlike previous models based on either coupled nonlinear Schrödinger or Ginzburg–Landau equations, can account for the dipole mechanism of light absorption and emission in erbium and carbon nanotubes, the slow relaxation dynamics of erbium ions and the absorption of erbium at the lasing wavelength. The researchers theoretically reproduced a new chaotic attractor for parameters close to the experimental ones. As well as being of fundamental interest, the findings are technologically significant as they permit the development of new types of lasers with controlled dynamic states of polarization.

Credit: © 2014 NPG