Ultrasensitive sensors based on specialty optical fibres

Abstract

Specialty optical fibres such as photonic-crystal, microstructured, multicore, and polymer optical fibres enable the design of a myriad of sensors. Different physical parameters, as for example, strain, temperature, vibration, force, etc., can modulate or perturb the guided light in a specialty optical fibre by means of elasto- or thermo-optic effects, in a similar manner than they do in standard optical fibres. In most cases the performance of sensors based on specialty fibres are comparable to those based on conventional fibres with the disadvantage that their fabrication is more complex and/or time consuming. In our group, however, we have devised compact, compellingly simple, ultrasensitive interferometric sensors based on photonic crystal fibres (PCF) and multicore optical fibres (MCFs) which are capable to sense a single or multiple parameters. In general, our devices operate in reflection mode and consist of a few centimetres of PCF or MCF fusion spliced to standard single-mode optical fibre. To fabricate and interrogate our devices we use tools and instrumentation widely used in the telecommunications industry. Our sensors can compete with well-established sensors based on standard optical fibres or on other specialty fibres. We believe that the high sensitivity and simplicity of our sensors make them attractive for practical applications.