Abstract
The index-guiding PCF basic structure is a solid core surrounded by a microstructured cladding. Owing to the presence of air holes, the effective refractive index of the cladding is below that of the core and the light is guided along the core by the principle of total internal reflection. Several authors have presented different geometries for this type of fibre and one of them is the suspended-core structure, where relatively large holes surround the fibre core that looks suspended along the fibre axis by small width silica walls. The chapter is divided in two parts. The first is about the fabrication of suspended core fibre and the second part is about the main applications of this type of fibres as interferometers.

Abstract
The intrinsic advantages of optical sensor technology are very appealing for high voltage applications and can become a valuable asset in a new generation of smart grids. In this paper the authors present a review of optical sensors technologies for electrical current metering in high voltage applications. A brief historical overview is given together with a more detailed focus on recent developments. Technologies addressed include all fiber sensors, bulk magneto-optical sensors, piezoelectric transducers, magnetic force sensors and hybrid sensors. The physical principles and main advantages and disadvantages are discussed. Configurations and strategies to overcome common problems, such as interference from external currents and magnetic fields induced linear birefringence and others are discussed. The state-of-the-art is presented including commercial available systems.

Abstract

Abstract
A temperature-independent strain sensor using a fibre Bragg grating written in an array fused taper is presented. This structure shows a spectrum with several peaks where their relative amplitudes are independent of temperature variations but change with applied strain. © 2006 OSA/OFS 2006.

Abstract
A new approach for a fibre optic modal Mach-Zehnder interferometer based on the combination of a fibre taper cascaded with a fibre LPG is presented. It is also demonstrated that such a structure can be applied for the implementation of a fibre optic inclinometer sensor. © 2006 Optical Society of America.

Abstract
A phase-shifted long-period fiber grating sensor fabricated by electric arc technique is used to measure bending curvature and temperature. © 2006 Optical Society of America.