Multiplexed high temperature sensing with sapphire fiber air gap-based extrinsic Fabry-Perot interferometers.

In this Letter we present a high temperature multipoint sensing method using sapphire fiber air gap-based extrinsic Fabry-Perot interferometers. Three sensors are fabricated and tested in a single sensing link. Experimental results show that the air gap-based high temperature sensors have a very high temperature sensitivity (>20 nm/ degrees C) and resolution (<0.3 degrees C) and are capable of operating at temperatures well above 1000 degrees C. The multiplexed sapphire sensors present a significant advancement over traditional single-point sensors for critical high temperature applications.