ABSTRACT
Distributed strain sensors are dominated by Brillouin technology, particularly at long distances; at shorter distances, Rayleigh optical frequency-domain reflectometry (OFDR) has a clear applicability alongside, or independently of Brillouin scattering. This chapter discusses some of the applications, emerging or established, of distributed strain sensors. Placing fibres of different types in the same cable will ensure that their temperature is equal for all practical purposes, but this is not necessarily the case for their strain, and so a fibre design incorporating multiple cores within a single glass structure might be more suitable. The practical issues in exposing a fibre to pressure that were discussed previously are even more acute in chemical sensing because the fibre must be exposed directly to the fuids being sensed. The measurement itself is similar in concept to the work of Geiger and Dakin, but taken much further towards a practical deployment.
