Entanglement-based high-accuracy chromatic dispersion measurements
Résumé
Quantum optical metrology enables phase sensitive measurements with a resolution beyond the classical Heisenberg limit. Here, we demonstrate a novel quantum metrology scheme for entanglement-enhanced chromatic dispersion (CD) measurements in short fibres and samples. Besides the expected doubled phase sensitivity, exploiting energy-time and path entanglement allows eliminating the major inconveniences of classical measurements based on white light interferometry (WLI). Our experimental procedure is significantly faster compared to the classical counterpart, and entanglement permits to further exploit a more simplified fitting function. Using these advantages, we measure CD in a 1 m long standard telecom fibre (Corning SMF28e) with an accuracy on top of the state-of-the-art, i.e. with an 1.7 times improved accuracy compared to the classical strategy.