Approaching the Non-Linear Shannon Limit

Abstract

Abstract-We review the recent progress of information theory in optical communications, and describe the current experimental results and associated advances in various individual technologies which increase the information capacity. We confirm the widely held belief that the reported capacities are approaching the fundamental limits imposed by signal-to-noise ratio and the distributed non-linearity of conventional optical fibres, resulting in the reduction in the growth rate of communication capacity. We also discuss the techniques which are promising to increase and/or approach the information capacity limit.

High-Capacity Directly Modulated Optical Transmitter for 2-μm Spectral Region

“…However, the capacity-transmission distance product is ultimately limited by fiber nonlinearity [1]. The record reported transmission capacity for SMF is now within about a factor of 2 of its theoretical maximum defined by the nonlinear Shannon limit [2]- [3]. However, as a result of the exponentially increasing volume of internet traffic, today's telecom networks are rapidly being driven towards their capacity limits, sparkling concerns over a potential future "capacity crunch" [4].…”

Reduced waiting times using a fast switching dual-polarization DDQPSK receiver in a packet switched network

“…The LMS Stokes parameter estimation scheme described in 6 works on the basis that the s 1 , s 2 and s 3 parameters for DP-mPSK form a flat surface/lens in the 3D space of (s 1 , s 2 , s 3 ). By calculating the slope of this plane, the polarization rotation angles of the Jones matrix can be determined, allowing for a polarization demultiplexing Jones matrix to be calculated.…”

“…At the same time, the non-linear Shannon capacity of singlemode fibre is being reached 2 . One way to improve data rates further in the network is to improve temporal utilization of network resources by performing optical packet switching (OPS) and spectral utilisation through coherent detection of polarisation multiplexed modulation formats.…”

Multi-Element Fibre for Space-Division Multiplexed Transmission

“…However, there is limited scope remaining for exploiting further single mode fibres (SMFs), since current techniques are already approaching the Shannon-limit [3]. Therefore, growing attention is now being focused on increasing the number of spatial channels in the fibre using space-division multiplexing (SDM) [4,5].…”