Patent ID: 7864389

Claim:
A method of performing error-free shut down of an optical power amplifier in an optical link comprising a transmitting side of said link, an optical fiber span and a receiving side of said link, wherein said optical power amplifier is a transmitting side power amplifier or a receiving side power amplifier; the method comprises shutting down said optical power amplifier in case of essentially simultaneously detecting at least two of the following events at the side of said link associated with the optical power amplifier: drop of input signal in a main band carrying information optical channels; power reduction in both the main band and a short band of signals: at the input of said amplifier if being the receiving side power amplifier, or at the output of said amplifier if being the transmitting side power amplifier; disappearance of a first diagnostic signal, if transmitted to the side of the link associated with said power amplifier from the other side of the link disappearance of a second diagnostic signal, if transmitted to the side of the link associated with said power amplifier from the other side of the link; wherein, in case said amplifier is the transmitting side power amplifier of said optical link, belonging to a bi-directional optical link, shutting down said amplifier upon detecting the following events: the drop or Loss of Signal (LOS) in the main band of informational optical channels to be applied to the input of the transmitting side power amplifier, the reduction of power both in the main band and in the short band at the output of the transmitting side power amplifier.