CCS and Power Systems
Crosscutting Research - Plant Optimization Technologies
Single-Crystal Sapphire Optical Fiber Sensor Instrumentation
Performer: Center for Photonics Technology
Project No: FC26-99FT40685
This system utilizes a sapphire-based fiber and a sapphire wafer to form a point sensor (Figure 1) that is referred to as an extrinsic Fabry-Perot interferometric (EFPI) sensor. The EFPI sensor records temperature data from inside the gasifier at temperatures up to 1,600 °C.
The project approach is based on the optical path difference (OPD) between reflections from the two surfaces of a sapphire wafer. The two reflections will interfere with each other, producing a modulated spectrum, the pattern of which is determined by the optical thickness (OT) of the wafer. The OT is the product of the refractive index and the thickness of the wafer, both of which have thermal dependence, resulting in a temperature-sensitive OT and spectrum. Therefore, the temperature can be determined from the change in the reflected spectrum.
Single-crystal sapphire sensor heads with sapphire fiber waveguides achieve greater precision through miniaturization.