Theory of radiation trapping by the accelerating solitons in optical fibers

TL;DR

This paper develops a theoretical framework explaining how Raman solitons in optical fibers trap normally dispersive radiation through an inertial gravity-like force, elucidating the continuous blue shift observed in supercontinuum spectra.

Contribution

It introduces a novel theory describing radiation trapping by accelerating solitons, highlighting the inertial force mechanism and providing analytical calculations of frequency shift rates.

Findings

The trapping effect is due to an inertial gravity-like force in the accelerating frame.

The rate of blue shift of trapped radiation exceeds the soliton’s red shift.

This theory explains the high-frequency edge shift in supercontinuum spectra.

Abstract

We present a theory describing trapping of the normally dispersive radiation by the Raman solitons in optical fibers. Frequency of the radiation component is continuously blue shifting, while the soliton is red shifting. Underlying physics of the trapping effect is in the existence of the inertial gravity-like force acting on light in the accelerating frame of reference. We present analytical calculations of the rate of the opposing frequency shifts of the soliton and trapped radiation and find it to be greater than the rate of the red shift of the bare Raman soliton. Our findings are essential for understanding of the continuous shift of the high frequency edge of the supercontinuum spectra generated in photonic crystal fibers towards higher frequencies.