Patent ID: 6665456
Filing Date: 2003-12-16
Classification: A61B,G01B,G01N,G01P

Abstract:
A dual channel optical reflectometer comprising:a broad bandwidth optical light source; an optical source path incorporating a depolarizing element that decorrelates optical signals in orthogonal fiber polarization channels and optically connects both channels to a path coupler; a path coupler that separates light into birefringent sample and reference paths while maintaining energy separation and decorrelation of optical signals in the fast and slow fiber polarization channels; a birefringent optical reference path optically connected to the path coupler and optically coupled to a scanning delay line; a birefringent optical sample path optically connected to the path coupler, wherein the birefringent sample path comprises a polarization channel separator/combiner, wherein the polarization separator-combiner divides/reunites optical signals in fast and slow polarization channels into two distinct optical beams that intersect at a single point in the sample under test, wherein the polarization channel separator is optically connected to a beam combiner that reunites optical signals in fast and slow polarization channels; the birefringent reference and sample paths are configured so that optical path length differences between fiber reference and sample paths in the fast and slow channels are less than one-half wavelength of incident light; a birefringent optical detection path optically connected to the path coupler and a polarization channel separator that is optically coupled to a first and second photoreceivers that produce first and second output signals, respectively, wherein the first and second output signals pass through a bandpass filter and amplifier; an analog-to-digital converter connected to the bandpass filter-amplifier; and a computer connected to the analog-to-digital converter.