Fast and slowly evolving vector solitons in mode-locked fibre lasers.

Area of Science:

• Optics and Photonics
• Nonlinear Fiber Optics
• Laser Physics

Background:

• Existing models for mode-locked fiber lasers often simplify the complex interactions within the laser cavity.
• Previous models based on nonlinear Schrödinger or Ginzburg-Landau equations do not fully capture the vector nature of light propagation and polarization dynamics.

Purpose of the Study:

• To develop a comprehensive vector model for erbium-doped fiber lasers mode-locked with carbon nanotubes.
• To overcome the limitations of previous models by incorporating crucial physical phenomena affecting polarization states.

Main Methods:

• Development of a novel vector model accounting for the vector nature of optical field interaction with the erbium-doped medium.
• Inclusion of slow relaxation dynamics of erbium ions.
• Consideration of linear birefringence in the fiber, cavity birefringence (linear and circular), and light-induced anisotropy from the pump field.

Main Results:

• The model successfully accounts for the interplay of various polarization-affecting factors within the laser cavity.
• A new family of vector solitons (VSs) with fast and slowly evolving polarization states has been identified.
• The findings demonstrate a departure from the behavior predicted by simpler, non-vectorial models.

Conclusions:

• The developed vector model provides a more accurate description of mode-locked erbium-doped fiber lasers.
• The newly discovered vector solitons exhibit unique polarization dynamics with potential for diverse applications.
• This research opens avenues for advanced laser design and novel applications in areas like secure communications and optical manipulation.