On the rigorous justification of b-modulation method and inclusion of discrete eigenvalues

Abstract

Addressing the optical communication systems employing the nonlinear Fourier transform (NFT) for the data modulation/demodulation, we provide the explicit proof for the properties of the signals emerging in the so-called b-modulation method, the nonlinear signal modulation technique that provides the explicit control over the signal extent. Our approach ensures that the time-domain profile corresponding to the b-modulated data has a limited duration, including the cases when the bound states (discrete solitonic eigenvalues) are present. In particular, in contrast to the previous approaches, we show that it is possible to include the discrete eigenvalues with the specially chosen parameters into the b-modulation concept while keeping the signal localization property exactly.