Is the Digital Twin of the Optical Transport the Enabler for Multi-Band Open and Disaggregated Optical Networks?

The largest portion of the installed optical fibers is the ITU-T G.652D that may enable a low loss transmission bandwidth exceeding 50 THz, so multi-band transmission is a solid cost-effective option to enable pay-as-you-grow network capacity growth. Moreover, the open and disaggregated network management is currently proposed by several consortia as an option for multi-vendor interoperability and infrastructure sharing and slicing. We comment on the need of a vendor agnostic digital twin of the physical layer to enable the openness, focusing on the peculiarities of the multi-band transmission scenario.