Dispersion management in optical networks using a differential phase shift keying modulation format

An optical communication system having a system bandwidth that includes a plurality of differential phase shift keying (DPSK) modulated channels, said system comprising:

• a transmitter configured to transmit a plurality of optical signals at different associated wavelengths within a signal band of wavelengths included in said system bandwidth using a DPSK modulation format, wherein said system bandwidth includes the entire range of said wavelengths at which optical signals are transmitted by said transmitter,
• a receiver configured to receive said plurality of optical signals;
• and
• a transmission path extending between said transmitter and said receiver, said transmission path establishing a negative average dispersion across said wavelengths with a minimum dispersion wavelength outside of said system bandwidth, said transmission path comprising at least one dispersion accumulation portion, said dispersion accumulation portion comprising a plurality of transmission spans and configured to allow accumulation of dispersion at a rate of −0.4 ps/nm/km or more negative for at least one of said wavelengths, said transmission path further comprising at least one dispersion compensation portion coupled to said dispersion accumulation portion and configured to compensate for at least a portion of the dispersion accumulated on said dispersion accumulation portion;
• wherein negative dispersion accumulated on said dispersion accumulation portion is returned to a zero or near zero dispersion level for said minimum dispersion wavelength at least in part by a dispersion compensation portion proximate said receiver.

A method of managing dispersion in an optical communication system having a system bandwidth that includes a plurality of differential phase shift keying (DPSK) modulated channels, said method comprising:

• transmitting a plurality of optical signals at different associated wavelengths within a signal band of wavelengths included in said system bandwidth using a DPSK modulation format, wherein said system bandwidth includes the entire range of said wavelengths at which optical signals are transmitted;
• allowing accumulation of chromatic dispersion at a rate of −0.4 ps/nm/km or more negative for at least one of said wavelengths as said optical signals propagate on a transmission path, wherein said transmission path establishes a negative average dispersion across said wavelengths such that negative dispersion accumulated on a dispersion accumulation portion of said path is returned to a zero or near zero dispersion level for a minimum dispersion wavelength that is outside of said system bandwidth;
• and
• compensating for chromatic dispersion in said optical signals after said allowing said chromatic dispersion to accumulate.