Patent ID: 7184660

Claim:
A method for monitoring performance of an optical network, comprising the steps of: selecting a group of optical signals traveling in the network; marking each of the optical signals in the selected group with a set of identification tags, each identification tag being unique to a network characteristic; and detecting the set of identification tags at various locations in the network; the step of marking comprising marking an optical signal, traveling through a section of fiber, with a fiber identification (FID) tag which is unique to the fiber section; and the step of detecting comprising detecting the fiber identification tag at various locations in the network; wherein the step of marking comprises modulating the optical signal so that identification tags are encoded onto the optical signal; wherein the step of modulating comprises modulating the optical signal with the identification tags, which are low frequency dither signals; wherein the step of modulating the optical signal with the low frequency dither signal is performed by an amplitude modulation; wherein the step of detecting comprises: tapping a portion of the optical signal; and determining one or more of the following parameters from the tapped portion of the optical signal: (a) frequency of the dither signal; (b) depth of modulation of the optical signal introduced by the dither signal; and (c) combined power of dither signals at the dither frequency.