Abstract
A novel fiber optic curvature sensor based on a core-offset single-mode fiber (SMF) and on a fiber Bragg grating (FBG) is presented. The FBG cladding modes are efficiently excited by the large core misalignment. The curvature of the beam can be obtained by the reflected power of the core mode and the recoupled cladding mode.

Abstract
In this work, a polymeric sensitive layer based on the acid-base equilibrium of phenol and of its derivative p-nitro-phenol is presented for carbon dioxide measurements. Thin films casted on glass slides were tested, using a LED source (lambda c at 410 nm) and an Ocean Optics USB4000 spectrometer, in the 0% to 15.25% CO2 concentrations range, showing a 40% maximum transmittance variation with a 51s response time and a 0.15% resolution. Preliminary results indicate that CO2 also induces refractive index changes in the sensitive layer. Using a fiber based interferometric setup, a CO2 dependent refractive index change of similar to 0.045 RIU was observed, in the 0%-90% CO2 concentration range.

Abstract
In this work, we present a fiber Bragg grating interrogation based on high-birefringence fiber loop mirror for strain-temperature discrimination. Due to spectral response of the optical filters it is possible to determine the variation of the wavelength and the optical power of the Bragg grating sensor when subject to strain or temperature. Maximum errors of +/- 0.4 degrees C and 12 mu epsilon are reported over 80 degrees C and 2000 mu epsilon measurement ranges. (c) 2006 Wiley Periodicals, Inc.

Abstract
In this letter, a novel radio-frequency finite impulse reponse (FIR) electrooptical configuration for self-referencing optical wavelength-division-multiplexed intensity sensors is reported. By employing the proposed low-cost electronic FIR filter at the reception stage, the use of a 14-km fiber delay coil is avoided for a 2-kHz modulation frequency, preserving sensitivity and self-reference. The technique is analyzed following the Z-transform formalism and measurements validating the theoretical model are reported.

Abstract
An optical current sensor based on a metal coated Hi-Bi fiber loop mirror is reported. This current sensor quantifies the current through the measurement of the temperature which varies accordingly with the magnitude of the electrical current. The temperature change is analyzed through the variation of the wavelength shift of a fringe minimum of a Hi-Bi fiber loop mirror. The minimum current detection was found to be approximately 10 A. (c) 2008 Wiley Periodicals, Inc.

Abstract
In the present paper, the influence of the fiber Bragg grating (FBG) length and its coating on embedded FBGs in polymers is evaluated. Different FBG lengths and coatings, uncoated and acrylate-recoated, are used. The evolution of their spectra is also followed during laminate curing on a hot-plate press. The Bragg gratings are used as optical fiber sensors, and their sensitivity and reliability are analyzed. The resulting sensor signal characteristics and the strain answers to different loading modes, i.e. tensile, flexural and through-thickness compression, are also studied.