Coded modulation of polarization- and space-multiplexed signals

Abstract

In this Paper we investigate the optimization of constellations for polarization-division multiplexed transmission in standard single-mode fiber systems and for space-division multiplexing in a multi-mode fiber system.

Replacing the Soft-Decision FEC Limit Paradigm in the Design of Optical Communication Systems

“…i.e., the GMI is a sum of bit-wise MIs between code bits and L-values. The equality in (25) does not hold, however, if the L-values were calculated using the max-log approximation (7), or more generally, if the L-values were calculated using any other approximation. For example, when max-log L-values are considered, it is possible to show that there is a loss in achievable rates.…”

“…This structure is known as BICM-ID and was introduced in [11]- [13]. BICM-ID for optical communications has been studied in [14]- [16], [7,Sec. 3], [17,Sec.…”

“…4.3] for the same purpose. The GMI, also known as the BICM capacity (or parallel decoding capacity), was introduced in an optical communications context in [7]. The performance of some LDPC codes with four-dimensional constellations over the additive white Gaussian noise (AWGN) channel was evaluated in terms of the GMI in [34].…”

On the Impact of Optimal Modulation and FEC Overhead on Future Optical Networks

“…The different networks under consideration are shown from left to right. In the throughput results, we also include the ideal network throughputs in Table II (solid horizontal lines) as well as the results obtained 7 This can be obtained by comparing the green pentagons for HD and SD FEC in Figs. 6 and 8. with QPSK and 7% FEC OH from Sec.…”

First Transmission of a 12D Format Across Three Coupled Spatial Modes of a 3-Core Coupled-Core Fiber at 4 bits/s/Hz

“…Some formats show natural resistance to nonlinear distortions like polarisation-division multiplexed quaternary phase shift keying (PDM-QPSK) being both constant power and on a cartesian grid (suitable for Gray mapping). Among advanced formats geared towards mitigating nonlinear effects, one notes formats resistant to phase distortions [8], shaped using shell mapping [9], 4D using points symmetrically located on two rings [12][13][14], 8D constellations based on selecting points within PDM-QPSK [10] or optimized for GMI [11], 12D [15] and 16D [16], the last two having large minimum distances but limited to low SE. So far, these formats have been implemented as time sequences of 4D symbols or across uncoupled fiber core on a single time slot.…”