Multidimensional modulation formats for coherent optical communications

Paper in proceeding, 2016

Coherent optical communication systems applying modulation formats with a dimensionality of four or higherare investigated and compared to systems using conventional formats. Higher dimensionality can be achieved by applying modulation over more than one polarization, time-slot, wavelength, mode or core. Both uncoded systems and systems applying forward-error correction (FEC) coding are studied in terms of spectral efficiency and sensitivity. It is shown that increasing the dimensionality for a constant spectral efficiency improves the sensitivity substantially if no coding is applied, whereas the corresponding gains generally are much smaller in FEC-coded systems.