High-Dimensional Modulation for Mode-Division Multiplexing

Abstract

We explore high-dimensional modulation for mode-division multiplexed optical fiber communication systems, focusing on optimized 24-D modulation formats in six-mode fiber transmission. Compared with conventional formats, our simulations demonstrate up to 8.7 dB span loss budget improvement for 6 b/s/Hz intra-channel spectral efficiency. Optical Fiber Communication Conference and Exposition (OFC)This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved. Abstract:We explore high-dimensional modulation for mode-division multiplexed optical fiber communication systems, focusing on optimized 24-D modulation formats in six-mode fiber transmission. Compared with conventional formats, our simulations demonstrate up to 8.7 dB span loss budget improvement for 6 b/s/Hz intra-channel spectral efficiency.

High-dimensional modulation for coherent optical communications systems

“…For block-coded modulation, we use the notation [N,p,h] -consistent with the coding literature -where h is the minimum Hamming distance of the code. Although this is not consistent with the notation used in our previous work [16][17][18][19][20], the large variety of codes used in this work necessitates this more generalized notation. In this section, we describe the design of such high-dimensional modulation formats using two approaches: spherical cutting of optimal lattices, and linear block codes over a base constellation of BPSK.…”

“…Although utilization of this concept in optical communications may be traced back to the first generation of coherent optical communications research in the 1980s [3], the concept was more recently re-introduced by Karlsson and Agrell [4,5] with polarization-switched quadrature phase shift keying (PS-QPSK) [6][7][8], set-partitioned quadrature amplitude modulation (SP-QAM) [9][10][11] and 6-polarization QPSK (6Pol-QPSK) [12] attracting particular interest from the research community. Research has also been conducted into the effects of expanding the number of modulation dimensions beyond 4, either by using multiple wavelengths [13,14], or time-slots [15][16][17][18][19][20][21] to map symbols in a modulation space of more than 4-D onto a 4-D carrier. Modulation techniques for many dimensions have also been investigated for carriers with more than four dimensions, particularly for systems which utilize spatial division multiplexing [20,22,23].…”

“…Research has also been conducted into the effects of expanding the number of modulation dimensions beyond 4, either by using multiple wavelengths [13,14], or time-slots [15][16][17][18][19][20][21] to map symbols in a modulation space of more than 4-D onto a 4-D carrier. Modulation techniques for many dimensions have also been investigated for carriers with more than four dimensions, particularly for systems which utilize spatial division multiplexing [20,22,23]. Bit-labeling across several consecutive 4-D symbols for constellations that do not have a cardinality (i.e.…”

“…separate high-dimensional block encoder and mapper), we considered joint encoding and mapping for lattice-cut modulation. We also note that although in this paper and our previous work on high-dimensional modulation [16][17][18][19][20] we have focussed on modulation with numbers of dimensions which are multiples of four, any number of dimensions may be used. This may be achieved by simultaneously generating four high-dimensional symbols, and serializing them independently onto each of the four carrier quadratures.…”

High-Dimensional Modulation for Optical Fiber Communications

“…In our previous research [11,[13][14][15][16][17], we have used the term "high-dimensional modulation" to refer to any modulation format with more than four dimensions. It should be noted however, that this terminology is not universal, and "multidimensional" is often used elsewhere in the literature -although this is also often used to describe 4-D modulation, which is relatively conventional in optical communications.…”