US Patent 11057146 Virtualized sections for sectional control of optical links

Systems and methods are implemented at an Optical Add/Drop Multiplexer (OADM) node using virtual sections to provide sectional control over an optical link over a foreign-controlled optical network. The systems and methods include obtaining and storing a first power spectral density snapshot of an optical link, from an optical spectrum monitor and when the optical link is in a non-fault condition; responsive to detection of a fault on channels traversing the optical link, obtaining a second power spectral density snapshot at a receiving end of the optical link; analyzing the first power spectral density snapshot and the second power spectral density snapshot; and determining the fault is on the optical link based on the analyzing.