We analyze and predict the performance of a fiber-optic temperature sensor from the measured fluorescence spectrum to optimize its design. We apply this analysis to an erbium-doped silica fiber by employing the power-ratio technique. We develop expressions for the signal-to-noise ratio in a band to optimize sensor performance in each spectral channel. We improve the signal-to-noise ratio by a factor of 5 for each channel, compared with earlier results. We evaluate the analytical expression for the sensor sensitivity and predict it to be approximately 0.02 °C<sup>−1</sup> for the temperature interval from room temperature to above 200 °C, increasing from 0.01 °C<sup>−1</sup> at the edges of the interval to 0.03 °C<sup>−1</sup> at the center, at 100–130 °C. The sensitivity again increases at temperatures higher than 300 °C, delineating its useful temperature intervals.
© 2003 Optical Society of America
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(060.2410) Fiber optics and optical communications : Fibers, erbium
(120.5630) Instrumentation, measurement, and metrology : Radiometry
(120.6780) Instrumentation, measurement, and metrology : Temperature
(300.2530) Spectroscopy : Fluorescence, laser-induced
Gonzalo Paez and Marija Strojnik, "Erbium-Doped Optical Fiber Fluorescence Temperature Sensor with Enhanced Sensitivity, a High Signal-to-Noise Ratio, and a Power Ratio in the 520–530- and 550–560-nm Bands," Appl. Opt. 42, 3251-3258 (2003)