Coherent Alien Waves over a DCM-compensated DWDM network

The optical network operated by GARR is based on two infrastructures that are separate, and employ different technologies. GARR-X, deployed in Central and Northern Italy since 2011, is optimized for Intensity Modulation with Direct Detection (IM-DD), 10Gb/s channels, where DCMs (Dispersion Compensating Modules) are used to compensate for chromatic dispersion. In Southern Italy, in the network called “GARR-X Progress”, a more innovative technology has been deployed operationally since the beginning of 2015. This GARR-X Progress infrastructure is DCM-free and is used for the transmission of coherent optical super-channels at 500Gb/s. The existence of these two different chromatic dispersion compensation techniques, and, for the near future, the need to potentially support only a small number of 100Gb/s client services on the original GARR-X infrastructure has led to plan a study of the performance, and possible limitations, of deploying coherent “alien” wavelengths over a DCM-based network. Our aim is to test the coexistence of native 10Gb/s IM-DD optical channels and coherent alien wavelengths of higher bit rate on the GARR-X infrastructure. For the 100Gb/s coherent signals we will use the same equipment deployed in GARR-X Progress, which is the Infinera DTN-X. The study is designed to test the performances of native IM-DD channels and alien coherent wavelengths which are transported simultaneously on the DCM-based infrastructure. We will test a range of scenarios that differ in the use of guard bands between channels of different technology, and for different coherent modulation schemes. The final goal is to determine if a smooth migration of the optical network in GARR-X towards the coherent model implemented in GARR-X Progress is feasible.



  • P.Bolletta
  • M.Carboni
  • G.Vuagnin

Part of session

Lightning Talks

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