Abstract
A compact fiber-optic inclinometer based on a fiber-taper Michelson interferometric sensor is constructed and demonstrated. The sensor consist of a single symmetrically taper waist of 80 mu m distanced 30 mm from the single-mode fiber end-tip right-angled cleaved. The amplitude of the bending angle of the fiber taper interferometer is obtained by passive interferometric interrogation based on the generation of two quadrature phase-shifted signals from two fiber Bragg gratings with different resonant wavelengths. Optical phase-to-bending sensitivity of similar to 1.13 rad/degree and a bend angle resolution of similar to 0.014 degree/root Hz were achieved.

Abstract
A novel configuration able to measure simultaneously relative humidity and temperature is proposed. The sensing head is based on a long-period fiber grating (LPG) coated with silica nanospheres in-line with a fiber Bragg grating. The polymeric overlay that changes its optical properties when exposed to different humidity levels is deposited onto the LPG using the electrostatic self-assembly technique (ESA), resulting into a humidity-induced shift of the resonance wavelength of the LPG. Considering the humidity range from 20% to 50% RH, a system resolution of 1.6% RH and 2.5 degrees C was achieved. At higher humidity, from 50% to 80% RH, the corresponding resolution values were 2.4% RH and 0.4 degrees C.

Abstract
A sensing head based on two fiber Bragg gratings arranged in a twisted configuration is proposed to measure three parameters simultaneously, namely 1) temperature, 2) strain, and 3) transverse load. One of the gratings is impressed into a high-birefringence fiber that provides two distinct spectral signatures, which, together with the signature of the second grating and the geometric characteristics of the sensing head, enable the degrees of freedom required to achieve the simultaneous measurement functionality. The resolutions achieved with this configuration for the measurement of temperature, strain, and transverse load are +/- 3.1 degrees C, +/- 46 mu epsilon, and +/- 0.01 N/mm, respectively.

Abstract
Three networks based on fused biconical wavelength division multiplexers (WDMs) and fiber Bragg gratings (FBGs) are theoretically and experimentally demonstrated for photonic-intensity-sensor multiplexing. The aim of replacing standard couplers for WDMs in the power division process is to reduce power losses and improve the robustness of the systems to FBG wavelength shifts. The different network topologies are analyzed both in terms of power budget and crosstalk noise, considering the multiplexing of two fiber-taper displacement sensors. The configuration with one detector for each sensor and the corresponding FBG at the detection end is proven to be the best topology in terms of crosstalk, doubling the peak-isolation value of the WDMs employed and yielding a 37.4-dB optical signal-to-noise ratio for a two-sensor network. Regarding power losses, the optimum configuration locates the FBGs at the sensor heads, thus improving power budget and avoiding additional couplers at the detectors. Both topologies are expanded to multiplex four sensors, being crosstalk identified as the critical factor in these networks. With this limiting parameter, the first configuration has been determined as the most suitable for multiplexing a high number of sensors.

Abstract
A micromachined low finesse Fabry-Perot interferometer for measuring dc and ac electrical current is presented. Interrogation of the microcavity is achieved by a dual-wavelength fiber Bragg grating technique working in quadrature. A linear relation between the dc electrical current and the optical phase defined by the microcavity was detected. Large enhancement of the sensitivity of the microcavities is presented with the use of a planar coil instead of a power line. The sensitivity of the sensor with the planar coil configuration is 7.9 rad/A and resolution of similar to0.18 mA/rootHz is achieved when the distance between the planar coil and the transducer head is 2 mm. The response of the sensor for ac measurements is 0.14 V/A with a resolution of 6 mA/rootHz when the distance between the power line and the transducer head is 5.5 cm.

Abstract
Singlemode-multimode-singlemode fiber structures (SMS) based on distinct sections of a pure silica multimode fiber (coreless-MMF) with diameters of 125 and 55 mu m, were reported for the measurement of curvature and temperature. The sensing concept relies on the multimode interference that occurs in the coreless-MMF section and, in accordance with the length of the MMF section used, two fiber devices were developed: one based on a bandpass filter (self-image effect) and the other on a band-rejection filter. Maximum sensitivities of 64.7 nm.m and 13.08 pm/degrees C could be attained, for curvature and temperature, respectively, using the band-rejection filter with 55 mu m-MMF diameter. A proof of concept was also explored for the simultaneous measurement of curvature and temperature by means of the matrix method.