Patent ID: 7773884

Claim:
An optical amplifier operative to monitor loss and return of an input signal in a wavelength division multiplexed (WDM) optical network carrying a plurality of WDM channels, comprising: a. a gain stage; b. a pump unit for supplying pump power to the gain stage; c. a first optical tap connected to an input to the amplifier; d. an optical channel monitor (OCM) coupled to the first optical tap and used for monitoring an optical power level of each WDM channel and for providing a respective electrical output; and e. a control unit for determining, based on the respective electrical output, an action affecting the pump unit; wherein the action is selected from the group consisting of a shut-down of the pump unit when the optical power level of each WDM channel is below a corresponding pre-defined first threshold, and start-up of the pump unit when the optical power level of at least one WDM channel is above a corresponding pre-defined second threshold.