Emergence of geometrical optical nonlinearities in photonic crystal fiber nanowires

TL;DR

This paper reveals a new type of optical nonlinearity in photonic crystal fiber nanowires that significantly reduces soliton Raman shifts, supported by analytical and numerical evidence.

Contribution

It introduces and explains a previously unknown nonlinear effect in photonic crystal fiber nanowires affecting soliton dynamics.

Findings

New nonlinear effect reduces soliton Raman self-frequency shift

Analytical and numerical methods confirm the phenomenon

Waveguide parameters strongly influence the nonlinearity

Abstract

We demonstrate analytically and numerically that a subwavelength-core dielectric photonic nanowire embedded in a properly designed photonic crystal fiber cladding shows evidence of a previously unknown kind of nonlinearity (the magnitude of which is strongly dependent on the waveguide parameters) which acts on solitons so as to considerably reduce their Raman self-frequency shift. An explanation of the phenomenon in terms of indirect pulse negative chirping and broadening is given by using the moment method. Our conclusions are supported by detailed numerical simulations.