Patent
1989-03-27
1991-07-23
LaRoche, Eugene R.
350 9614, 35016223, G02F 101, G02B 610, G02B 518
Patent
active
050338269
ABSTRACT:
An optical time-domain reflectometry (OTDR) system comprises an oscillator, a phase shifter, an amplifier, an optical pulse generator, an integrated electro-optical circuit, a detector, a timer, a converter, and an output device. The OTDR system can be used to determine which surface of a photographic lens is impairing transmissivity the most. When the amplifier is enabled, a signal from the oscillator starts the timer and triggers the pulse generator. The timer is a time-to-digital circuit with analog interpolation. The resulting pulse is transmitted through the integrated electro-optical circuit and into the lens being evaluated. The strongest reflection from the lens is detected and the resulting detection signal stops the timer. The timed duration is expressed by the converter as a distance which can be used to identify the lens surface of interest. The result is displayed and/or stored on the output device. An electrical waveform from the oscillator is conveyed along a transmission line defined by electrodes of the integrated electro-optical circuit. This waveform introduces phase distortion in the optical pulse conveyed along an optical path of the integrated electro-optical circuit. The phase shifter is programmed so that these phase distortions are approximately quadratic over the pulse duration, so that the frequency of the pulse is "swept" linearly. The integrated electro-optical circuit includes a dispersive grating which introduces time delay as a function of frequency. The combination of sweeping and dispersing results in a pulse which is compressed relative to its original form. The compressed pulse allows more precise identification of the surface causing the strongest reflection so that modern multi-element lenses can be effectively evaluated.
REFERENCES:
patent: 3724926 (1973-04-01), Lee
patent: 3795433 (1974-03-01), Channin
patent: 4251130 (1981-02-01), Marcatili
Treacy, E. B.: "Optical Pulse Compression with Diffraction Gratings", IEEE Journal of Quantum Electronics, vol. QE-5 #6, Sep. 1969; pp. 454-458.
Beaud et al.: "High Resolution Optical Time Domain Reflectometry for the Investigation of Integrated Optical Devices"--Institute of Applied Phys.; University of Bern, date prior to filing date.
Dolfi, D. W.: "Traveling-Wave 1.3 .mu.m Interferometer Modulator with High Bandwidth, Low Drive Power, and Low Loss", Applied Optics, vol. 25, Aug. 1986, pp. 2479-2480.
Nazarathy et al.: "Real Time Long Range Complementary Correlation Optical Time Domain Reflectometer", Journal of Lightwave Technology vol. 7 #1, Jan. 1989, pp. 24-38.
Peng et al.: "Theory of Periodic Dielectric Waveguides", IEEE Transactions on Microwave Theory and Techniques vol. MTT 23 #1, Jan. 1975; pp. 123-133.
Joseph A. Giordmaine et al., "Compression of Optical Pulses", IEEE Journal of Quantum Electronics, vol. QE-4, No. 5, May 1968, pp. 252-255.
Michel A. Duguay et al., "Optical Frequency Shifting of a Mode-Locked Laser Beam", IEEE Journal of Quantum Electronics, vol. QE-4, No. 4, Apr. 1978, pp. 238-242.
John K. Wigmore et al., "Temporal Compression of Light", IEEE Journal of Quantum Electronics, vol. QE-14, No. 8, Aug. 1968, pp. 252-255.
Hewlett--Packard Company
LaRoche Eugene R.
Lester Evelyn A.
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