Abstract

Abstract
We have studied the effect of gamma radiation on Long Period Fiber Grating (LPFG) temperature sensors fabricated in a pure-silica fiber, using the arc discharge technique. The temperature sensitivity of the LPFGs remains unchanged by the irradiation.

Abstract
A new scheme is presented for simultaneous measurement of strain and temperature using a sampled fibre Bragg grating based on a long period structure written using the electric are technique. The temperature and strain measurement resolutions are estimated to be +/-0.50degreesC/rootHz and +/-3.38 muepsilon/rootHz, respectively.

Abstract
The electric arc technique allows the inscription of long-period gratings (LPGs) virtually in all types of fibers, including non-photosensitive fibers, the case of non-Ge doped photonic crystal fibers being of particular interest. LPGs written in standard fibers using this technique have shown a high thermal stability. Also, the resistance to. - radiation of LPGs arc-induced in pure-silica-core fibers is being assessed and the achieved results are very promising. We have also demonstrated that the combination of arc-induced LPGs and UV-induced fiber Bragg gratings (FBGs) leads to sampled FBGs that are able to address sensing functionalities with enhanced performance. Therefore, as a result of their properties, gratings induced by arc-discharges can find a wide range of applications in optical communications as well as in fiber sensing.

Abstract
A study on arc-induced long-period fibre gratings (LPFGs) revealed that their strain sensitivity depends on the electric current of the arc discharge. Based on that property, a sensor scheme comprising two concatenated LPFGs was implemented for discrimination of temperature and strain effects. This sensor presented resolutions of +/-0.1 degreesC/rootHz and +/-35 muepsilon/rootHz, respectively.

Abstract
Permanent long-period gratings were written using arc discharges in two aluminosilicate fibers, one of which was doped with erbium. Reversible gratings were also mechanically induced in both fibers. The thermal behavior of the arc-induced gratings was investigated at up to 1100 degrees C. It was found that the shift of the resonant wavelengths exhibited a well-defined linear dependence on temperature up to 700 degrees C. (c) 2005 Optical Society of America.