Regeneration limit of classical Shannon capacity

Abstract

Since Shannon derived the seminal formula for the capacity of the additive linear white Gaussian noise channel, it has commonly been interpreted as the ultimate limit of error-free information transmission rate. However, the capacity above the corresponding linear channel limit can be achieved when noise is suppressed using nonlinear elements; that is, the regenerative function not available in linear systems. Regeneration is a fundamental concept that extends from biology to optical communications. All-optical regeneration of coherent signal has attracted particular attention. Surprisingly, the quantitative impact of regeneration on the Shannon capacity has remained unstudied. Here we propose a new method of designing regenerative transmission systems with capacity that is higher than the corresponding linear channel, and illustrate it by proposing application of the Fourier transform for efficient regeneration of multilevel multidimensional signals. The regenerative Shannon limit-the upper bound of regeneration efficiency-is derived.

Next-to-leading-order corrections to capacity for a nondispersive nonlinear optical fiber channel in the intermediate power region

“…The influence of nonlinearity on capacity is investigated both for dispersive and nondispersive optical channels. The channels with dispersion were studied in numerous papers, see, e.g., [2][3][4][5][6][7][8][9][10][11][12] and references therein. Despite the fact that the capacity for the nonlinear channel with dispersion was considered in many papers the exact in nonlinearity result is still not found due to difficulty of the problem.…”

Advanced 3R regenerator scheme for high spectral efficient signal waveforms

“…TF : y=x+α sin ( βx ) , and it enables suppression of distortion on multiple amplitude levels. It can be applied independently on the two signal quadratures using the three branch interferometric configuration that has been recently proposed in [4], and depicted in Fig. 1b).…”

“…Subsequently, the selected signal undergoes a 2R regeneration stage, where the two signal quadratures are separated and experience a non-linear Regenerative Fourier Transformation (RFT) [4]. The RFT represents the first order Fourier expansion of an ideal stepwise transfer function, i.e.…”

Classical capacity per unit cost for quantum channels

“…Since it is the energy budget that is the most sensitive resource in such settings it is crucial to increase the amount of information transmitted with a single unit of energy. Another example of a situation in which capacity per unit cost is well suited for the description of communication tasks is when the energy is spend not only on the modulation procedure, that is, generating a signal, but also on the propagation of the information carriers like in various signal regeneration techniques [25][26][27]. In such instances it is crucial to take into account the energy spent on regeneration, since it may modify the overall performance of the protocol.…”