Patent ID: 7444078

Claim:
A node of an optically amplified wavelength division multiplexing network, the node connecting at least one upstream optical fiber link to at least one downstream optical fiber link, comprising: a receiver amplifier, the receiver amplifier receiving an optical signal comprising a plurality of optical channels from the at least one upstream optical fiber link, the receiver amplifier further comprising at least one pump laser; an optical add/drop multiplexing module, the optical add/drop multiplexing module adapted to at least one of drop at least one of the plurality of optical channels, pass at least one of the plurality of optical channels, and add at least one of the plurality of optical channels; a transmitter amplifier, the transmitter amplifier amplifying the at least one of the plurality of optical channels passed and the at least one of the plurality of optical channels added; and an optical tap upstream of the receiver amplifier, the optical tap monitoring an optical signal power, the receiver amplifier amplifying the optical signal during normal operation and operating as a noise source generating an output noise power in response to a loss of signal from the at least one upstream optical fiber link being detected by the optical tap, wherein the receiver amplifier comprises circuitry to shut down the receiver amplifier after detecting the loss of signal, wherein the at least one upstream optical fiber link provides an input signal to at least one downstream amplifier with gain control circuitry, the circuitry of the receiver amplifier being adapted to shut down the receiver amplifier at a speed less than a speed of response of the gain control circuitry of the at least one downstream amplifier.