Multi-Wavelength Distributed Raman Amplification Set-Up

An apparatus comprising:

• a Raman amplifier comprising a plurality of Raman pump lasers configured to inject optical Raman pump power at a corresponding plurality of wavelengths into a second end of an optical fiber to achieve Raman amplification of an optical signal output by a controlled optical source at a first end of the optical fiber;
• a photodiode configured to detect power at the second end of the optical fiber;
• a controller coupled to the photodiode and to the Raman amplifier, wherein the controller is configured to:
• obtain a first receive power measurement with the controlled optical source turned on and with the plurality of Raman pump lasers turned off;
• obtain a second receive power measurement with the controlled optical source at the first node turned on and the plurality of Raman pump lasers turned on to respective reference power levels;
• compute a reference Raman gain based on the first receive power measurement and the second receive power measurement;
• compute a total power from the plurality of Raman pump lasers needed to achieve a target Raman gain in the optical fiber span based on the reference Raman gain and a sum of the respective reference power levels used by the plurality of Raman pump lasers to obtain the second receive power measurement;
• obtain, based on the target Raman gain and a target Raman gain tilt, respective ratios of the total power, each ratio to be used for a corresponding one of the plurality of Raman pump lasers;
• and
• set the power of each of the plurality of Raman pump lasers according to its respective ratio of the total power.

One or more tangible computer readable storage media encoded with software comprising computer executable instructions and when the instructions are executed by a processor, the processor is operable to:

• for an optical fiber span coupled between a first node and a second node, obtain a first receive power measurement at the second node with a controlled optical source at the first node turned on and with a plurality of Raman pump lasers at different wavelengths at the second node turned off;
• obtain a second receive power measurement at the second node with the controlled optical source at the first node turned on and the plurality of Raman pump lasers turned on to respective reference power levels to inject optical Raman pump power at a corresponding plurality of wavelengths into the optical fiber span;
• compute a reference Raman gain based on the first receive power measurement and the second receive power measurement;
• compute a total power from the plurality of Raman pump lasers needed to achieve a target Raman gain in the optical fiber span based on the reference Raman gain and a sum of the respective reference power levels used by the plurality of Raman pump lasers used to obtain the second receive power measurement;
• obtain, based on the target Raman gain and a target Raman gain tilt, respective ratios of the total power, each ratio to be used for a corresponding one of the plurality of Raman pump lasers;
• and
• set the power of each of the plurality of Raman pump lasers according to its respective ratio of the total power.