Sensing characteristics of hollow-core photonic crystal fibre modal interferometers

In this work, sensitivity to strain, temperature and curvature of a sensor relying on modal interferometry in hollow-core photonic crystal fibre is studied. The sensing structure is simply a piece of hollow-core fibre connected in both ends to standard single mode fibre. An interference pattern that is associated to the interference of the light that propagates in the hollow core fundamental mode with light that propagates in other modes is observed. The phase of this interference pattern changes with the measurand interaction, which is the basis for considering this structure for sensing. The phase recovery is performed using a white light interferometric technique.