Abstract

In ultra-long-haul optical communication systems, polarization-dependent gain from single-mode semiconductor optical amplifiers or mode-dependent gain from multi-mode erbium-doped fiber amplifiers causes a channel’s achievable information rate (AIR) using linear minimum-mean-square error (MMSE) detection to become substantially lower than the capacity of optimal maximum likelihood detection owing to loss of orthogonality between modes. However, such capacity loss can be mitigated using techniques that retain reasonable complexity, such as successive interference cancellation (SIC). In wireless systems, multicarrier transmission with many subcarriers transforms the frequency-selective channel into a set of uncoupled memoryless subchannels, and it is possible to obtain good performance using SIC on each subchannel independently. Multicarrier transmission in optical fibers, however, is susceptible to performance loss caused by Kerr nonlinearity. Therefore, we study methods for applying SIC on frequency-selective optical fiber channels using single-carrier transmission. We compare the theoretical performance of MMSE and SIC equalizers on frequency-selective optical fiber channels operating at 64 Gbaud with transmission distances up to 15,000 km and evaluate the penalties of SIC implementation. We consider single-mode fiber links with random artificial polarization-mode dispersion inserted along the link to enhance frequency diversity, as well as multi-core fiber links supporting 14 spatial and polarization modes. We show that SIC can increase outage capacity by 19%, but the AIR increase is reduced by almost half if error correction coding is not performed across modes. We confirm that SIC can adapt to fast channel perturbations with only a 3% decrease in AIR.

Demonstration of 10-channel mode- and polarization-division multiplexed free-space optical transmission with successive interference cancellation DSP

Yiming Li, Zhouyi Hu, David M. Benton, Abdallah Ali, Mohammed Patel, and Andrew D. Ellis
Opt. Lett. 47(11) 2742-2745 (2022)

Mode-dependent loss and gain: statistics and effect on mode-division multiplexing

Keang-Po Ho and Joseph M. Kahn
Opt. Express 19(17) 16612-16635 (2011)

Chip-interleaved optical code division multiple access relying on a photon-counting iterative successive interference canceller for free-space optical channels

Xiaolin Zhou, Xiaowei Zheng, Rong Zhang, and Lajos Hanzo
Opt. Express 21(13) 15926-15937 (2013)

BER analysis of an optimum MIMO linear receiver in optical SDM systems with mode-dependent loss

Luis M. Torres, Francisco J. Cañete, and Luis Díez
Opt. Express 31(20) 31671-31686 (2023)

Impact of mode coupling on the mode-dependent loss tolerance in few-mode fiber transmission

Adriana Lobato, Filipe Ferreira, Maxim Kuschnerov, Dirk van den Borne, Sander L. Jansen, Antonio Napoli, Bernhard Spinnler, and Berthold Lankl
Opt. Express 20(28) 29776-29783 (2012)