Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1992-10-07
1993-11-02
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
25022714, H01J 516
Patent
active
052586146
ABSTRACT:
A fiber optic loop temperature sensor employs a fiber optic loop (90) having a predetermined fixed radius where a light source (96) supplies light to the signal optical fiber (92) with the loop and a second reference optical fiber (100) receives light from the light source (96) for providing a reference light intensity. The light intensities from both optical fibers are measured and the temperature is determined from differences therein. Advantageously, the fiber optic loop temperature sensor is employed in a temperature compensated, self-referenced fiber optic microbend pressure transducer to compensate for thermal offset of the microbend sensor output. In the preferred embodiment, time division multiplexing provides at least two bi-cell photodetectors (82) with output and source signals for generating a log ratio output for determining the sensed parameter independent of cable and connector offsets and light source fluctuations in addition to compensation for thermal offset. An alternate embodiment uses time domain intensity referencing.
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Berthold John W.
Kidwell J. Jeffrey
Reed Stuart E.
Davenport T.
Edwards Robert J.
Kalka Daniel S.
Matas Vytas R.
Nelms David C.
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