Thermostatized Flow Cell and Hybrid LPG-FBG Configuration for Accurate Measurement of Refractive Index

The design and characterization of a thermo-stabilized low-volume flow cell for accurate refractive index measurements using a hybrid cascaded configuration of optical fiber gratings are presented. The sensing system consists of a long period grating, which is sensitive to the refractive index of the medium surrounding the fiber, and of a methodology for correcting the sensor cross-sensitivities. This is based on a fiber Bragg grating and a thermocouple. The proposed sensing system was preliminary tested as biosensor by means of the implementation of an IgG/anti-IgG immunoassay.