Electrostriction and guidance of sound by light in optical fibers

TL;DR

This paper explores how light can generate and guide sound waves in optical fibers through electrostriction, revealing mechanisms for phonon wavepacket formation and guidance relevant to Brillouin scattering.

Contribution

It provides a theoretical framework for phonon generation and guidance in optical fibers, matching experimental spectra and identifying mechanisms for forward and backward interactions.

Findings

Reproduces experimental spectra in standard and photonic crystal fibers.

Identifies elastic resonances dominating forward interactions.

Discovers efficient phonon guidance by light in backward interactions.

Abstract

We investigate the generation of phonon wavepackets in optical fibers via electrostriction from coherent optical waves. Solving the elastodynamic equation subject to the electrostrictive force, we are able to reproduce experimental spectra found in standard and photonic crystal fibers. We discuss the two important practical cases of forward interaction, dominated by elastic resonances of the fiber, and backward interaction, for which an efficient mechanism of phonon guidance by light is found. The latter result describes the formation of the coherent phonon wavepacket involved in stimulated Brillouin scattering.