Self-referenced point temperature sensor based on a fluorescence intensity ratio in Yb^3+-doped silica fiber

Abstract
An optical fiber temperature sensor, based on the fluorescence intensity ratio from the 2F5/2a and 2F5/2b Stark sublevels in ytterbium-doped silica fiber, has been investigated. Results of a sensor prototype demonstrate an accuracy near 1 °C in a 600 °C temperature range. Changes in the fluorescence intensity ratio because of variation in pump power, pump wavelength, and induced fiber bending loss are demonstrated to be small, supporting development of a practical sensor based on the technique described.