Cascaded LPG and FBG integrated in a miniaturized flow cell for compensated refractometric measurement

The present paper describes the design and characterization of a thermo-stabilized flow cell for accurate refractive index (RI) measurements using a long period grating (LPG)-based sensor and a methodology to measure and correct all the LPG cross-sensitivity. A fiber Bragg grating (FBG) written on the same fiber in series with the LPG and an accurate measuring system of the temperature are used in order to minimize the interferences coming from temperature and strain changes. The experimental results show that the proposed system provides good performance as far as the RI sensitivity and resolution are concerned. The maximum RI sensitivity and resolution are around 1.455 RIU and the values are 3,120nm/RIU and 2 x 10 -5 RIU, respectively. © 2012 Springer Science+Business Media, LLC.