Dual Strain and Temperature Sensor Using a Fluorescence Intensity Ratio in Er³⁺ -doped Fibre Combined with a Fibre Bragg Grating

Overcoming the problem of temperature cross sensitivity inherent in optical fibre strain sensors is currently of much interest. Many groups are investigating this cross sensitivity in fibre Bragg grating (FBG) sensors by seeking ways to have both parameters determined simultaneously from two separate sensor elements having different temperature and strain responsibities. Clearly both parameters can be obtained simultaneously provided the two separate sensor elements have different temperature and strain responsibilities. This paper reports measurements of temperature and strain using the proposed sensing scheme, in an erbium-doped fibre