Temperature-dependent fluorescence characteristics of an ytterbium-sensitized erbium-doped silica fiber for sensor applications

The characteristics of temperature-dependent fluorescence of an ytterbium (Yb3+)-sensitized erbium (Er3+)-doped silica fiber are presented. A 10-cm long double-clad Yb3+/Er3+-codoped fiber is diode-pumped at 915 nm and the individual fluorescence intensities from Yb3+ and Er3+ ions are measured with varying the fiber temperature. The ratio of the dual fluorescence intensities varies exponentially with temperature in the range of room temperature to similar to 300 degrees C. This dual-dopant system has dual emission bands that emit comparable fluorescence powers. Particularly, the self-referencing fluorescence intensity ratio is insensitive to external perturbations in the fiber, which is useful for sensors that are used in a harsh environment without any use of additional referencing techniques. This scheme allows a compact, long-life, and low-cost temperature sensor and can also be combined with a wide range of existing fiber-optic multiplexing schemes that can simultaneously detect multiple physical parameters. (c) 2005 Elsevier Inc. All rights reserved.