Variable optical reflector for simultaneous strain and temperature measurement

We present a fibre optic sensing system for simultaneous strain and temperature measurement based on a narrow band variable optical reflector. The variable optical reflector comprises a single mode fibre Bragg grating and a fibre mode converter. A 2 µm m −1 strain resolution is achievable over a range of 2000 µm m −1 with a temperature accuracy of 0.3 °C. A strain sensor with a range of 12 000 µm m −1 is also demonstrated. The sensing system shows high strain and temperature sensitivities with very good stability.