Polarization noise induced by photon-phonon interaction in hollow-core photonic crystal fibres

In this study, we perform quantum-noise-limited measurements in an 8 metres long HC-PCF and observe polarization noise at sideband frequencies in the MHz range when using a pulsed laser. The measurement shows more polarization noise peaks than in solid core fibres with similar fibre diameter. We analyse the acoustic eigenmodes in the HC-PCF with finite element simulations using COMSOL Multiphysics. For each measured polarization noise peak, we are able to identify a corresponding acoustic mode.