Determination of local high temperature excursion in an intrinsic doped fiber fluorescence-based sensor

A fluorescence-based intrinsic doped fiber temperature sensing system for determining local extremes of high temperatures has been demonstrated in this work. Data on this temperature rise are analyzed using a mathematical relationship, based on a correlation coefficient ratio scheme, to relate to the reduced fluorescence decay time information thus associated with the hot part of the fiber. In schemes incorporating this mathematical analysis, two separate sensor configurations have been demonstrated, one of which is to use short, single lengths of fiber spliced into a network and the other a long single length of doped fiber, using both Nd and Er doped fiber materials. The results show that the correlation coefficient ratio, R, will deviate from and be smaller than unity with the increase of the temperature of the localized region where the heat is applied, providing the mechanism for a simple high temperature excursion detection system.