Novel sapphire fiber thermometer using fluorescent decay

A novel sapphire fiber thermometer using fluorescent decay is presented. The thermal probe is simply a sapphire fiber grown from the laser heated pedestal growth (LHPG) method, with its end doped with Cr3+ ion. The sapphire fiber is coupled with a normal Y-shape silica fiber bundle for signal transmission. Signal processing system for the fluorescent lifetime detection is set up. Relationship of the fluorescent lifetime and intensity with the temperature for the doped sapphire fiber is carefully measured and presented. The thermometer has good thermal response characteristics due to its specific thermal probe structure. The coupling efficiency between the fiber probe and the guiding fiber bundle is also high and stable. Experimental result shows that the thermometer has an average temperature resolution of 1 degrees C between 20 and 450 degrees C. (C) 1998 Elsevier Science S.A. All rights reserved.