Method and apparatus for saturating an optical amplifier chain to prevent over amplification of a wavelength division multiplexed signal

摘要

An optical signal processing method and apparatus for providing a noise feedback loop that uses existing noise within the optical system to saturate a chain of amplifiers after the branching unit, thereby preventing information channels in a WDM signal containing empty channels from becoming overamplified as they pass through downstream amplifiers. The method and apparatus uses an existing drop amplifier which emits ASE noise as a side effect. A coupler connects the ASE noise to a filter. The filtered ASE noise is fed into an existing trunk amplifier by a second coupler. The trunk amplifier increases gain to the filtered ASE noise to a level high enough to saturate the amplifier chain, without requiring an external noise generating device.