Rayleigh Scattering From Multimode Optical Fibres At Very High Temperatures

Normal multimode graded-index optical communication fibres have been operated at temperatures up to 1200°C with a view to determining their suitability for communication and sensing applications in very high temperature environments. To this end, scattering from fibres which have been repeatedly heated to temperatures up to 1200°C has been investigated with an OTDR operating at 850 nm. A complicated variation of scattering with temperature has been observed, particularly during the first heating of the fibre. However, with suitable pre-treatment the fibre scattering may be used for distributed temperature sensing at temperatures up to about 800°C. Above this temperature the fibre has limited life due to rapid crack propagation and breaking.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.