Dual polarization nonlinear Fourier transform-based optical communication system

Eigenvalue communication is considered an emerging paradigm in fiber optics communications, as it can overcome the limitations imposed by nonlinearity to the standard linear communication systems. Eigenvalue communication, relying on the powerful mathematical technique known as "inverse scattering transform (IST)" -also called "nonlinear Fourier transform (NFT)"- exploits the "hidden" linearity of the nonlinear Schrödinger equation as the master model for signal propagation in an optical fiber. This can potentially remove the nonlinearity as a source of signal distortion by making it, instead, an essential part of the nonlinear communication channel. We present here the theoretical tools describing the NFT for the Manakov system (MS) and report on the first experimental transmission results for dual polarization in fiber optics eigenvalue communications. A transmission of up to 373.5 km with bit error rate (BER) less than the hard-decision forward error correction (HD-FEC) threshold has been achieved, using 2 quadrature phase shift keying (QPSK) modulated discrete eigenvalues of the MS nonlinear spectrum and exploiting the Darboux transformation to generate the signal waveforms. Our results pave the way towards an increased spectral efficiency of NFT-based communication systems, which are currently based on single polarization channels.