We experimentally show Brillouin-enhanced four-wave mixing for optical chiral states in twisted photonic crystal fiber, demonstrating topology-selective cross-frequency information transfer that occurs only when pump and probe have opposite circular polarization. The paper can be found here.

Authors: Xinglin Zeng, and Birgit Stiller

Abstract:
Brillouin-enhanced four-wave mixing (BE-FWM) - also known as Brillouin dynamic gratings - is an important nonlinear effect in photonics that couples four light waves by traveling acoustic waves. The effect has received much attention in the past few decades, especially for applications in fiber sensing, signal processing, and optical delay lines. Here, we report BE-FWM with optical chiral states (i.e., circular polarization and vortex states) in twisted photonic crystal fiber, by leveraging the topology-selective Brillouin effect. Phase-matching has the consequence that the traveling acoustic gratings created by circularly polarized vortex pump and Stokes in the stimulated Brillouin scattering can be used to modulate a frequency-shifted probe, where the pump/Stokes and probe have different circular polarization or topological charges. Based on our findings, we demonstrate cross-frequency selective information transfer and show that the information is transferred only when pump and probe have opposite circular polarization.