Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1982-10-27
1985-01-22
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250231R, G01D 534
Patent
active
044954115
ABSTRACT:
A fiber optic sensor for detecting and/or measuring a physical quantity varying at any frequency from a maximum desired frequency down to zero frequency with minimum disturbance from environmentally induced perturbations. A first highly birefringent optical fiber is positioned longitudinally adjacent to a second equally birefringent fiber. Each fiber has orthogonally disposed fast and slow axes. The fibers are oriented such that their fast axes are perpendicular to each other. When subjected to stress caused by a physical quantity acting on the fibers through a transducer, the birefringence of each of the two fibers is asymmetrical altered thereby rotating the states of polarization of coherent light signals passing through the two fibers in a common direction. Environmental perturbations symmetrically alter the birefringence of each of the fibers thereby rotating the states of polarization of the light signals in opposite directions. The states of polarization of the light signals emanating from the two fibers are detected and combined such that the changes due to the physical quantity enhance each other while the changes due to environmental perturbations are cancelled.
REFERENCES:
patent: 3591254 (1971-07-01), Browne
patent: 3605013 (1971-09-01), Yoshikawa
patent: 3693082 (1972-09-01), Jaecklin
patent: 3786681 (1974-01-01), Kiehn
patent: 3950987 (1976-04-01), Slezinger et al.
patent: 4070620 (1978-01-01), Feldtkeller et al.
patent: 4111050 (1978-09-01), Waddoups
patent: 4162397 (1979-07-01), Bucaro et al.
patent: 4173412 (1979-11-01), Ramsay et al.
patent: 4295738 (1981-10-01), Meltz et al.
patent: 4363114 (1982-12-01), Bucaro et al.
patent: 4433915 (1984-02-01), Hanse
patent: 4442350 (1984-04-01), Rashleigh
patent: 4450406 (1984-05-01), Bobb
patent: 4468090 (1984-08-01), Ulrich et al.
Ulrich, Rashleigh, Eickhoff, "Bending-Induced Birefringence in Single-Mode ibers" Optical Letters, Jun. 1980, vol. 5, No. 6, pp. 273-275.
Ulrich, "Polarization Stabilization on Single-Mode Fiber".
Appl. Phys. Lett. 35 (11); Dec. 1, 1979; pp. 840-842, Kaminow, Simpson, Presby, "Strain Birefringence in Single-Polarisation Germanosilicate Optical Fibres" Electronics Letters; vol. 15, No. 21; Oct. 11, 1979, pp. 677-679.
Rashleigh, Ulrich, "Magneto-Optic Current Sensing with Birefringent Fibers" Appl. Phys. Lett. 34 (11), Jun. 1, 1979, pp. 768-770.
Layton, Bucaro, "Optical Fiber Acoustic Sensor Utilizing Mode-Mode Interference" Applied Optics, vol. 18, No. 5, Mar. 1, 1979, pp. 666-668.
Stolen, Ramaswamy, Kaiser, Pleibel, "Linear Polarization in Birefringent Single-Mode Fibers" Appl. Phys. Lett. 33 (8), Oct. 15, 1978, pp. 699-701.
Simon, Ulrich, "Evolution of Polarization Along a Single-Mode Fiber" Applied Phys. Lett. vol. 31, No. 8, Oct. 15, 1977, pp. 517-519.
Papp, Harms, "Polarization Optics of Liquid-Core Optical Fibers" Applied Optics, vol. 16, No. 5, May 1977, pp. 1315-1319.
Papp, Harms, "Polarization Optics of Index-Gradient Optical Waveguide Fibers" Applied Optics, vol. 14, No. 10, Oct. 1975, pp. 2406-2411.
Kapron, Borrelli, Keck, "Birefringence in Dielectric Optical Waveguides" IEEE Journal of Quantum Electronics, vol. QE-8, No. 2, Feb. 1972, pp. 222-223.
Dyott, Stern, "Group Delay in Glass-Fibre Waveguide" Electronics Lett., vol. 7, No. 3, Feb. 11, 1971, pp. 82-84.
Beers Robert F.
Brophy Jere J.
Ellis William T.
Forrest John L.
Nelms David C.
LandOfFree
Fiber optic sensors operating at DC does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fiber optic sensors operating at DC, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fiber optic sensors operating at DC will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-568212