US Patent 9762319 Real-time Raman gain monitoring

Techniques are described for determining, with a first optical node, a correction factor indicative of an amount of optical power loss that a Raman amplifier in a second optical node causes in an optical signal having a first wavelength that is transmitted by the first optical node and received by the second optical node, transmitting, with the first optical node to the second optical node, information, based on the determined correction factor, that is to be used for determining a gain of the Raman amplifier, and transmitting, with the first optical node to the second optical node, an optical signal having a second wavelength that is to be amplified by the Raman amplifier.