title: Solitons beyond binary: possibility of fibre-optic transmission of two bits per clock period.
abstract: Optical telecommunication employs light pulses travelling down optical fibres; in a binary format logical Ones and Zeroes are represented by the presence or absence of a light pulse in a given time slot, respectively. The fibre's data-carrying capacity must keep up with increasing demand, but for binary coding it now approaches its limit. Alternative coding schemes beyond binary are currently hotly debated; the challenge is to mitigate detrimental effects from the fibre's nonlinearity. Here we provide proof-of-principle that coding with solitons and soliton molecules allows to encode two bits of data per clock period. Solitons do not suffer from nonlinearity, rather, they rely on it; this endows them with greater robustness. However, they are universally considered to be restricted to binary coding. With that notion now refuted, it is warranted to rethink future systems.
authors.affiliation: Institute for Physics, University of Rostock, Universitätsplatz 3 , 18055 Rostock,  Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Rohrmann
authors.forename: Alexander
authors.initials: A
authors.lastname: Hause
authors.forename: Fedor
authors.initials: F
authors.lastname: Mitschke