Fiber-Optic Temperature Sensor For Microwave Environments

An all optical fiber interferometric temperature sensor suitable for microwave environments is discussed. The sensor is capable of continuously and accurately monitoring temperatures safely and reliably. The transducer features small volume (as small as .35 mm in diameter and 2 mm in length), with an operating temperature span of 22.5°C that may be centered about a specific temperature in the range of 50°C to >250°C. Because phase modulation is employed, the transducer can be hundreds of meters from the demodulation package. Since it uses Fabry-Perot geometry, it exhibits minimal lead sensitivity. The fiber-optic system is constructed of all dielectric material and thus is immune to EMI. The sensor has a resolution of .002°C and an accuracy of ±.01°C. It can be packaged in an array to measure temperatures at multiple locations.