Optics: measuring and testing – By dispersed light spectroscopy – Utilizing a spectrometer
Patent
1997-08-26
1999-11-02
Turner, Samuel A.
Optics: measuring and testing
By dispersed light spectroscopy
Utilizing a spectrometer
G01C 1972
Patent
active
059780843
ABSTRACT:
A signal processing circuit (10) for a fiber optic sensor (12) includes a d.c. block (14) coupled to the fiber optic sensor (12) for removing d.c. components from the fiber optic sensor output signal, and a low pass filter (16) coupled to the d.c. block (14) for reducing noise in the fiber optic sensor output signal and generate a filtered signal. A comparator (18) is coupled to the low pass filter (16) and generates a squared signal indicative of zero crossings in the filtered signal. A lock-in amplifier or synchronous demodulator (20) is coupled to the comparator (18) and generates an output signal indicative of a phase shift in the two light waves propagating in the fiber optic sensor (12).
REFERENCES:
patent: 4456376 (1984-06-01), Carrington et al.
patent: 4545682 (1985-10-01), Greenwood
patent: 4578639 (1986-03-01), Miller
patent: 4613811 (1986-09-01), Vaerewyck et al.
patent: 4615582 (1986-10-01), Lefevre et al.
patent: 4733938 (1988-03-01), Lefevre et al.
patent: 4779975 (1988-10-01), Kim
patent: 4894608 (1990-01-01), Ulmer, Jr.
patent: 4947107 (1990-08-01), Doerfler et al.
patent: 4973899 (1990-11-01), Jones et al.
patent: 5034679 (1991-07-01), Henderson et al.
patent: 5051577 (1991-09-01), Lutz et al.
patent: 5056885 (1991-10-01), Chinn
patent: 5063290 (1991-11-01), Kersey
patent: 5133600 (1992-07-01), Schroder
patent: 5157461 (1992-10-01), Page
patent: 5181078 (1993-01-01), Lefevre et al.
patent: 5270791 (1993-12-01), Lefevre et al.
patent: 5297436 (1994-03-01), Chan et al.
patent: 5455676 (1995-10-01), Nishiura et al.
patent: 5644397 (1997-07-01), Blake
J. Blake, et al., "In-Line Sagnac Interferometer Current Sensor," 1995 IEEE Transactions on Power Delivery, No. 1, Jan., 1996.
Deeter, Merritt N., "Fiber-optic Faraday-effect magnetic-field sensor based on flux concentrators," Applied Optics, vol. 35, No. 1, Jan. 1, 1996.
R.T. de Carvalho, J. Blake, and G. Sanders, "Sagnac Interferometers for Accurate Measurements of True Nonreciprocal Effects", SPIE, vol. 2070, pp. 264-269.
Kent B. Rochford, Gordon W. Day, and Peter R. Forman, "Polarization Dependence of Response Functions in 3x3 Sagnac Optical Fiber Current Sensors", Journal of Lightwave Technology, vol. 12, No. 8, Aug. 1994, pp. 1504-1509.
P.A. Nicati and Ph. Robert, "Stabilised Current Sensor Using Sagnac Interferometer", IOP Publishing Ltd., 1988, pp. 791-796.
H. Taylor, "Fiber Sensors: 2", U.S. Naval Research Laboratory, Apr. 29, 1981, pp. 128-130.
P.A. Nicati and Ph. Robert, "Stabilized Sagnac Optical Fiber Current Sensor Using One Phase and Two Amplitude Modulations", Swiss Federal Institute of Technology of Lausanne, pp. 402-405.
I.G. Clarke, D. Geake, I.M. Bassett, S.B. Poole, and A.D. Stokes, "A Current Sensor Using Spun Birefringent Fibre in a Sagnac Configuration", OFTC, University of Sydney, Australia, pp. 167-170.
A. Yu and A.S. Siddiqui, "A Theoretical and Experimental Investigation of a Practicable Fibre Optic Current Sensor Using Sagnac Interferometer", Department of Electronic Systems Engineering, University of Essex, pp. 289-292.
L.R. Veeser and G.W. Day, "Faraday Effect Current Sensing Using a Sagnac Interferometer With a 3x3 Coupler", National Institute of Standards and Technology, pp. 325-328.
P. Akhavan Leilabady, A.P. Wayte, M. Berwick, J.D.C. Jones, and D.A. Jackson, "A Pseudo-Reciprocal Fibre-Optic Faraday Rotation Sensor: Current Measurement and Data Communication Applications", Elsevier Science Publishers B.V., pp. 173-176.
R.A. Bergh, H.C. Lefevre, and H.J. Shaw, "Geometrical Fiber Configuration for Isolators and Magnetometers", Fiber-Optic Rotation Sensors and Related Technologies, Springer Series in Optical Sciences 32, 1982, pp. 111-116.
Guido Frosio and Rene Dandliker, "Reciprocal Reflection Interferometer for a Fiber-Optic Faraday Current Sensor", Applied Optics, vol. 33, No. 25, Sep. 1, 1994, pp. 6111-6122.
R.T. de Carvalho and J. Blake, "Simultaneous Measurement of Electric and Magnetic Fields Using a Sagnac Interferometer", Texas A&M University, College Station, Texas.
F. Maystre, et al., "Magneto-optic Current Sensor Using a Helical Fiber Fabry-Perot Resonator", Springer Proceedings in Physics, vol. 44, 1989.
J.N. Ross, "The rotation of the polarization in low birefringence monomode optical bivres due to geometric effects", Qpitcal and Quantum Electronics 16, pp. 455,461, 1984.
Oho, Shigeru, Hisao Sonobe and Hiroshi Kajioka, "Time-Domain Sagnac Phase Reading in Open-Loop Fiber Optic Gyroscopes", IEICE Trans Electron, vol. E79 C. No. 11, pp. 1596-1601, Nov. 1996.
The Texas A&M University System
Turner Samuel A.
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