Abstract
The measurement of refractive index (RI) is an important tool for label free biosensing in biomedical applications [1,2]. In this work, a LPG based fiber optic interferometric probe is used for thrombin detection. The aptamer raised against the thrombin was immobilized through an electrostatic immobilization method, using poly-L-lysine as cationic polymer. The functionalized probe was characterized and tested against thrombin. The system was validated with the detection of thrombin using an aptamer based probe (5'-[ amine]GGTTGGTGTGGTTGG-3') as a model system for protein detection. The shift corresponding to the affinity-assay between TBA and the thrombin was of about 56 pm. A differential readout interferometer based on a white light Mach-Zehnder configuration, with pseudo-heterodyne phase modulation is described. The system can be used to interrogate two similar LPGs based interferometers in a differential scheme. Considering the configuration where both devices are functionalized being one active (sensor) and the other one passive ( reference) it is possible to accurately measure the behavior of the analyte of interest independent of non-specific binding events, bulk refractive index changes and temperature. Signal processing with low cost digital instrumentation developed in Labview environment allows a detectable change in refractive index of Delta n approximate to 2x10(6) [3]. Coupling the sensing probe together with a passively functionalized reference probe in a differential system will enable pseudo-heterodyne interrogation and extremely sensitive phase detection of biological species.

Abstract
A fiber optic sensor for simultaneous measurement of refractive index and temperature is presented. The sensing probe is realized by introducing a multimode interference device inside a high birefringence fiber loop mirror resulting in a configuration capable of refractive index and temperature discrimination. The multimode interference peak is sensitive to the surrounding refractive index (90 nm/RIU) and slightly responsive to the temperature (0.01 nm/ degrees C). On the other hand, the birefringent fiber loop mirror is highly sensitive to temperature (2.36 nm/ degrees C) and it has almost no response to refractive index. Using a power ratiometric peak detection scheme, a temperature independent refractive index measurement can be achieved with a resolution of +/- 2.25 x 10(-5) RIU.

Abstract
The wine sector is a billion euro business and therefore subjected to multiple attempts of fraudulent practices. This requires the development of rapid and reliable methods to detect such situations. Several methodologies have been developed based on the chemical profiles of the wines, but they are limited due to the environmental conditions that cannot be controlled. The use of DNA-based detection systems are an emergent research field that have been extended to a wide variety of food products and are still the most reliable methods for varietal identification. However these methods are not suitable for geographical determination. Soil related fingerprints have a primary role considering that there is a relationship between the elemental composition of wine and the composition of the provenance soil. WineBioCode is a project aiming to define the best strategy for wine authenticity based on a multidisciplinary approach. Two DNA-based strategies have been developed based on Real-time PCR and a label free optical biosensor platform. Both platforms enabled successful identification of specific DNA-targets when applied to Vitis vinifera L., and can be applied throughout the grape-wine chain. The methods are complementary and can be used in different situations, according to the requirements. The geographical evaluation has been assessed by the strontium 875r1865r isotope ratio determination involving soil evaluation in the vineyards followed by its assay in the wine samples. The results are being integrated in order to establish the best procedure to be undertaken for wine fingerprinting, including varietal composition and geographical origin, therefore fulfilling the requirements of the geographical denominations in wine certification.

Abstract
A long-period grating (LPG) written on a standard single mode fiber is investigated as a fiber optic sensor for vibration and magnetic field sensing. It is demonstrated the high sensitivity of the device to applied curvature and the possibility to monitor vibration in a wide range of frequencies from 30 Hz to 2000 Hz. The system was tested using intensity-based interrogation scheme, providing a frequency discrimination of 913 mHz. The goal of these tests was to evaluate the sensor as a passive vibration monitor in the detection of changes in resonant vibration frequencies of support infrastructures can provide information on its degradation. Furthermore, taking advantage of the intrinsic sensitivity to micro strain, alternating magnetic fields were also measured using an intensity-based interrogation scheme by coupling a Terfenol-D magnetostrictive rod to a pre-strained LPG sensor, providing a resolution below 5.61 mu T-rms/root Hz from 1.22 mT(rms) up to 2.53 mT(rms).

Abstract
A high sensitivity refractive index sensor based on the combination of mechanically induced long period gratings (LPG) and fiber tapers was developed for real-time fuel quality analysis. The sensor was built in a Mach-Zehnder configuration by employing a pair of in-series gratings. In order to enhance sensor sensitivity, the region between both LPGs was tapered down from 125 to 10 mu m. The system was tested by measuring water concentration in ethanol and ethanol concentration in commercial gasoline. The tapered sensor has shown an average sensitivity of 930 nm/RIU, 18 times higher than the non-tapered version. The resolution limit of the system using spectral interrogation was estimated to be 0.06% of ethanol dissolved in gasoline. For the purpose of real-time monitoring, an interrogation system based on white light interferometry (WLI) and virtual instrumentation was employed to evaluate ethanol evaporation in water, avoiding the use of spectral analysis. The WLI system, using phase tracking techniques, enabled us to record the evolution of the ethanol concentration in water with a resolution of 0.005% (v/v).

Abstract
Nafion has been evaluated as a sensing phase of an optical fibre humidity sensor based on a low-finesse Fabry-Perot interferometer. The sensor was constructed by manual deposition of a drop of a Nafion solution on the tip of a single mode optical fibre, forming a Fabry-Perot resonant cavity. The absorption of water by the Nafion film makes it swells, changing its refractive index and the length of the cavity, which produces a phase shift in the interference signal. The sensitivity, stability and response time of the sensor were evaluated in the RH range from 22 to 80% by analysing the correspondent reflection spectra of the interference fringes. As a result, it was obtained that Nafion can be used as sensing phase of an optical fibre humidity sensor based on optical fibre Fabry-Perot interferometry, presenting a response time of 242 ms (3% RH variation) and a sensitivity of 3.5 nm/%RH.