Reduction of ASE in WDM optical ring networks

A wavelength division multiplexed optical communication system comprising:

• an optical fiber ring configured to carry a wavelength division multiplexed optical communication signal, the wavelength division multiplexed optical communication signal comprising plural optical channels at different wavelengths;
• a plurality of optical fiber amplifiers interposed along the optical fiber ring for optically amplifying the wavelength division multiplexed optical communication signal;
• means for injecting an optical wavelength into the optical fiber ring at a first location, the optical wavelength being located within a region of spontaneous emission for the optical fiber amplifier such that the injected optical wavelength reduces amplified spontaneous emission in at least two optical amplifiers in the optical fiber ring;
• means for dropping the optical wavelength from the optical fiber ring at a second location, the second location positioned such that the injected optical wavelength is dropped at or prior to returning to the first location within the ring, the second location additionally being positioned such that the optical wavelength passes through at least two of the plurality of optical amplifiers before being dropped from the optical fiber ring such that amplified spontaneous emission from a first optical fiber amplifier is substantially removed from the optical fiber ring before being input to that optical fiber amplifier in a subsequent traversal of the optical fiber ring.