In-service defragmentation in optical networks using wavelength conversion

Abstract

A system for in-service defragmentation may identify optical signals having wavelengths within a first predefined optical wavelength band for transition from a current channel to an alternate channel within the first band and may determine directions and amounts by which to move the wavelengths. The identified wavelengths in the first band may be slowly and deliberately drifted by the determined amounts, using multiple incremental adjustments, and converted to corresponding wavelengths in a second predefined optical wavelength band for transmission. During the transitions, the drifting optical signals in the second band may be combined with optical signals remaining in their current channels in the first band for transmission. Once the wavelength transitions are complete, the transitioned optical signals may be transmitted on their alternate channels in the first band. Collections of wavelength transitions that do not cross each other may be identified and may be performed substantially in parallel.