Abstract
In this work, an all-fiber loop mirror using a clover microstructured fiber for the simultaneous measurement of temperature and strain is presented. The sensing head is formed by a short piece of clover microstructured fiber with 35 mm length. The geometry of the fiber allowed observing different interferences created by the microstructured fiber core section. Different sensitivities to temperature and strain were obtained and, using a matrix method, it is possible to discriminate both physical parameters. Resolutions of ±2°C and ±11 µe, for temperature and strain, respectively, were attained. © 2012 SPIE.

Abstract
This paper presents a sensing head based on a Bragg grating written in an elliptical cladding Hi-Bi fibre partially exposed to chemical etching for reduction of the cladding diameter. With this sensing head geometry different strain and similar temperature sensitivities are achieved.

Abstract
The application of hollow-core photonic crystal fibers for gas sensing is reviewed and discussed. Some problems with splicing to standard fibers and gas diffusion into the core are addressed. Current work at INESC Porto in the development of sensing heads and interrogation units is also reported.

Abstract
A review of optical fiber sensing demonstrations based on photonic crystal fibers is presented. The text is organized in five main sections: the first three deal with sensing approaches relying on fiber Bragg gratings, long-period gratings and interferometric Structures; the fourth one reports applications or these fibers for gas and liquid sensing; finally, the last section focuses oil the exploitation of nonlinear effects in photonic crystal fibers for sensing. A brief review about splicing with photonic crystal fibers is also included.

Abstract
A brief review on suspended-core fibers for sensing applications is presented. A historical overview over the previous ten years about this special designed microstructure optical fiber is described. This fiber presents attractive optical properties for chemical/biological or gas measurement, but it can be further explored for alternative sensing solutions, namely, in-fiber interferometers based on the suspended-core or suspended-multi-core fiber, for physical parameter monitoring. © The Author(s) 2012.

Abstract
A sensing head for simultaneous measurement of temperature and strain is presented and analyzed. The proposed configuration is based on the combination of two Bragg gratings, written in different fibres and with different reflectivities, to form a single signature with a reflected step spectrum profile. This characteristic minimizes the spectrum allocated to each sensor in a series multiplexing topology. By measuring the changes in the peak wavelength and spectral width of this signature, resolutions of +/- 0.65 degrees C/root Hz and +/- 2.55 mu epsilon/root Hz were achieved for temperature and strain measurements, respectively.