Abstract
This presentation gives a review of the main concepts behind fibre optic sensing networks. Some important application areas are mentioned, such as the monitoring of oil fields, of large Civil Engineering structures, as well as of natural environments. Then, it will be addressed the potential relevance of this technology in domains of increasingly social importance, such as Health and Elderly Care, particularly in the development of Personal Health Systems.

Abstract
An optical refractometer based on a birefringent (Hi-Bi) fiber Bragg grating (FBG) written in a new H-shaped fiber structure is proposed. This structure is formed by opening the two holes of a side-hole fiber using chemical etching. When the Hi-Bi FBG is immersed in different liquids, different responses of the slow and fast wavelengths are obtained. The refractometer is also capable of simultaneous measurement of refractive index and temperature. (c) 2008 Optical Society of America OCIS codes: 060.2310, 060.3735, 060.2370.

Abstract
A Fabry-Perot refractometer based on the suspended core fibre is presented. The Fabry-Perot cavities are formed by a section of suspended core fibre between conventional single-mode fibres. This miniature refractive tip sensor is demonstrated for the measurement of the refractive index change by measuring the fringe visibility and through the analysis of the fast Fourier transform. The two methods are compared. The temperature dependence was also characterized. [DOI: 10.2971/jeos.2009.09041]

Abstract
In this paper, it is presented a brief review of the sensing applications using suspended core fibres. Since the first publication, several authors have studied their properties and possible applications in engineering. Due to their geometry, the great potential in optical sensing is in bio and gas sensing. Recently, with the possibility of inscribing Bragg grating structures on these fibres, it is possible to use them for other applications. Finally, this paper reviews the recent works with suspended core fibres for interferometry.

Abstract
A fiber optic sensing system for simultaneous measurement of refractive index and temperature, based on a hybrid fiber Bragg grating/long-period grating arrangement is described. The experimental results show that this setup has a good performance in terms of linearity and sensitivity, the ratiometric output changes 4%/0.001 RIU and 3.6%/degrees C, respectively. The sensor resolution for the refractive index is approximate to 2 x 10(-5) RIU. The simultaneous measurement of the refractive index and temperature was demonstrated. The sensing configuration has the ability to be read-out in reflection and works in the telecommunications window.

Abstract
A self-referenced passive optical network (PON) with coarse wavelength division multiplexing (CWDM) is reported for remotely addressing optical intensity sensors with enhanced sensitivity. The self-referencing remote configuration is described as a finite-impulse-response (FIR) filter in reflective operation using two fiber Bragg gratings (FBG) and a fiber delay line. The antisymmetrical phase response of the configuration permits to achieve a self-referencing measurement parameter two times more sensitive than reported previously. To enhance the power budget of the network, CWDM devices with low insertion losses are used for spectral splitting of a radio-frequency (RF) modulated broadband light source (BLS). The network topology and the sensor's interrogation technique are theoretically analyzed and experimental results validating the models are reported.