Provisioning, Recovery, and In-Operation Planning in Elastic Optical Networks

1 Motivation

Luis Velasco and Marc Ruiz

Universitat Politècnica de Catalunya, Barcelona, Spain

1.1 Motivation

The huge amount of research done in the last decade in the field of optical transmission has made available a set of technologies jointly known as flexgrid, where the optical spectrum is divided into 12.5 GHz frequency slices with 6.25 GHz central frequency granularity, in contrast to the coarser 50 GHz in fixed grid Wavelength Division Multiplexing (WDM) [G694.1]. Such frequency slices can be combined in groups of contiguous slices to form frequency slots of the desired spectral width, thus increasing fiber links’ capacity. To illustrate the magnitude of the capacity increment, a 40 Gb/s connection modulated using Dual‐Polarization Quadrature Phase Shift Keying (DP‐QPSK) can be transported on a 25 GHz slot in flexgrid, instead of 50 GHz needed with WDM [Ru14.1].

In addition to increasing network capacity, subsystems currently being developed will foster devising novel network architectures. These are as follows:

• Liquid Crystal on Silicon (LCoS)‐based Wavelength Selective Switches (WSS) to build flexgrid‐ready Optical Cross‐Connects (OXCs) [Ji09].
• The development of advanced modulation formats to increase efficiency, which are capable of extending the reach of optical signals [Ge12].
• Sliceable Bandwidth‐Variable Transponders (SBVTs) able to deal with several flows in parallel, thus adding, even more, flexibility and reducing costs [Sa15].

The resulting flexgrid ...