A new coherent optical detection technique employing coherent frequency-domain reflectometry and a novel optical frequency sensor is demonstrated for high-precision optical path-length measurements. Using pulsed laser sources,an improvement of more than two orders of magnitude in spatial resolution over conventional optical coherent frequency domain reflectometry techniques is demonstrated. Varying degrees of spatial resolution ranging from several centimeters to a few hundred nanometers are achieved. High-precision distance measurement with long baseline is also presented.
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