Field Trial toUpgrade anExisting 10Gbit/s DWDM Linkby 40Gbit/s RZ-DQPSKChannels

Datarates generated intheaccess network bynewservices andcustomer demand ontriple play influence onthe transmission capacity andflexibility ofthetransport network. A field trial toupgrade anexisting DWDM link with10Gbit/s RZ-andNRZ-channels by40Gbit/s RZ-DQPSK-channels wasperformed onalink consisting of legacy G.652fibre withtwoROADM andEDFAamplification only. Thefield link hadalength of1047km. Toobtain ahighspectral efficiency ofthe40Gbit/s transport thechannel spacing wasreduced from100GHzto 50GHz.We investigated channel crosstalk for50GHzand100GHzchannel spacing, mixedtypes ofneighbour channels, PMD andchromatic dispersion tolerance whichinfluence onmaximumtransparent transmission length andsignal quality ofthe40Gbit/s signal inafield experiment.