High-Temperature Fiber-Optic Sensor for Low-Power Measurement of Wide Dynamic Strain Using Interferometric Techniques and Analog/DSP Methods

An optic fiber-based sensor design is presented, suitable for use at high temperatures (up to 750°C) for measurement of the frequency of dynamic strain having wide magnitude range. The design and optimization of the location of the fiber sensor on a diaphragm structure, in two interferometer configurations is analyzed. The complete signal extraction and evaluation with signal processing electronics and DSP algorithm is realized in low power (under 15 mW). The challenge in the implementation of this technology is the need to perform under difficult industrial conditions namely, very large temperature range, high pressure dynamics, good chemical corrosion resistance, high measuring range, high sensitivity, vibration immunity, and low-power operation.