Patent ID: 7280189

Claim:
A system for testing optical networks in an optical network having a trunk optical fiber having a proximal and a distal ends, the trunk being coupled to at least one splitter at its distal end, the splitter being further coupled to a plurality of feeder optical fibers, at least one of the feeder fibers being coupled to an Optical Network Terminal (ONT), the ONT having an optical passband filter having a at least one optical frequency rejection zone for attenuating signals in frequencies within the rejection zone, the system comprising: an Optical Time Domain Reflectometer (OTDR) coupled to the trunk at or near its proximal end; wherein the OTDR having a transmitter tuned to produce optical waves in a primary frequency within the rejection zone, for the OTDR to couple transmitted waves to the trunk; and a receiver tuned to receive reflected optical waves at a primary frequency within the rejection zone, for receiving the transmitted optical waves reflected from the optical network, wherein a set of reflected waves forms a first signature; and, wherein the optical filter is characterized with at least one high passband and at least one low passband, and wherein the rejection zone is interposed between the high passband and low passband.