Patent ID: 8395763
Filing Date: 2013-03-12
Classification: G01M

Abstract:
1. A method of measuring change in power loss in a passive optical element defining an optical propagation path, comprising: a. coupling a first end of a first buffer fiber to an input of the optical propagation path, coupling a second end of the first buffer fiber to an optical time domain reflectometer (OTDR), and coupling a first end of a second buffer fiber to an output of the optical propagation path, b. employing the OTDR to launch optical radiation into the first buffer fiber via the second end thereof, measure power level of return light received at the OTDR via the second end of the first buffer fiber, and create a first OTDR signature representing power level of return light as a function of distance from the second end of the first buffer fiber, c. selecting a first marker point by applying data reduction to at least a portion of a segment of the first OTDR signature corresponding to the first buffer fiber, d. selecting a second marker point downstream of the output of the optical propagation by applying data reduction to at least a portion of a segment of the first OTDR signature corresponding to the second buffer fiber, e. calculating a first power difference value as difference between a power level at the first marker point and a power level at the second marker point, f. subsequent to step b., employing the OTDR to launch optical radiation into the first buffer fiber via the second end thereof, measure power level of return light received at the OTDR via the second end of the first buffer fiber, and create a second OTDR signature representing power level of return light as a function of distance from the second end of the first buffer fiber, g. selecting a third marker point by applying data reduction to at least a portion of the segment of the second OTDR signature corresponding to the first buffer fiber, the third marker point being at substantially the same location as the first marker point, h. selecting a fourth marker point by applying data reduction to at least a portion of a segment of the second OTDR signature, the fourth marker point being at substantially the same location as the second marker point, i. calculating a second power difference value as difference between a power level at the third marker point and a power level at the fourth marker point, and j. subtracting one of the first and second power difference values from the other power difference value.