Development of fiber-optic interferometric temperature sensor system /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | A temperature sensing system utilizing an internal-mirror fiber Fabry-Perot interferometer (FFPI) as a sensor head is developed. The system is based on the detection scheme called the "Quadrature Detection Method" which uses the chirping of the laser diode to determine the direction of the temperature change and to adjust the sensor's effective operating point to near the maximum sensitivity point of the interferometer. The scheme also utilizes a reference FFPI to compensate for the wavelength drift of the laser diode light source, due to temperature variations in the environment. The sensor head consists of a continuous length of single mode silica fiber which contains two internal mirrors a distance of about 1 cm apart to form the interferometer cavity. The temperature change produces changes in both the refractive index and physical length along the interferometer cavity, resulting in modulation of the reflected optical signal propagating in the fiber. Fringe shifts caused by thermally induced chirping of the pulsed laser diode are utilized in the processing scheme. Possible noise sources are analyzed to determine the best performance possible in a high sensitivity instrument. The sensor system can operate from -250 to 1050 °C with a system-limited sensitivity of 0.001 °C. Attractive features include freedom from RFI/EMI, wide temperature range, high sensitivity, fast response, point sensing capability, geometrical versatility, resistance to corrosion, and ability to be multiplexed. The temperature sensor is developed as a stand-alone system which has its own an LCD display and a control keypad. Laboratory experiments have verified the ability of the signal processing to provide a digital temperature readout and to determine the direction of temperature change. Finally, some applications and possibilities for system upgrade for sensing other variables and multiplexing are briefly reviewed. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Electrical Engineering." |
| Physical Description: | xi, 169 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |