Flow cell for strain- and temperature-compensated refractive index measurements by means of cascaded optical fibre long period and Bragg gratings

An optical fibre sensing system based on a hybrid cascaded long period grating (LPG) and fibre Bragg grating configuration and a thermo-stabilized flow cell for refractometric measurements is proposed. The system makes it possible to measure, and thus to cancel, the LPG cross-sensitivities to strain, temperature and fibre bending. The experimental results show that the proposed system provides satisfactory performances as far as the refractive index sensitivity and resolution are concerned. The maximum sensor sensitivity and resolution are 3120 nm/RIU and 2 × 10 -5 RIU, respectively. The whole system with its flow cell and the gratings fabrication are extensively described, together with the acquisition and data processing. The stability of the sensor for several hours was also tested. We believe that the proposed system can be successfully used for label-free chemical/biochemical sensing

Spectroscopic characterization and optical waveguide fabrication in Ce(3+), Tb(3+) and Ce(3+)/Tb(3+) doped zinc-sodium-aluminosilicate glasses

A spectroscopy investigation of Ce3+ and Tb3+ ions in sodium-zinc-aluminosilicate glasses is performed using the photoluminescence technique. Blue-white light, with x = 0.24 and y = 0.24 CIE chromaticity coordinates, is obtained for the Tb3+ singly-doped glass excited at 351 nm. When the sodium-zinc-aluminosilicate glass is co-doped with Ce3+ and Tb3+ a non-radiative energy transfer from Ce3+ to Tb3+ ions is observed upon 320 nm excitation. From an analysis of the cerium emission decay curve, the Ce3+ -> Tb3+ energy transfer microscopic parameter and efficiency are obtained. Different concentrations of Ce3+ and Tb3+ ions in the glass host gives rise to blue and blue-green emissions, with different Ce3+ coordinates. Optical waveguides were produced in the samples by Ag+-Na+ ion-exchange, and their characterization is presented. (C) 2011 Elsevier B.V. All rights reserved