Abstract

The increase in capacity provided by coupled space division multiplexing (SDM) systems is fundamentally limited by mode-dependent gain (MDG) and amplified spontaneous emission (ASE) noise. Therefore, monitoring MDG and optical signal-to-noise ratio (SNR) is essential for accurate performance evaluation and troubleshooting. Recent works show that the conventional MDG estimation method based on the transfer matrix of multiple-input multiple-output (MIMO) equalizers optimizing the minimum mean square error (MMSE) underestimates the actual value at low SNRs. Besides, estimating the optical SNR itself is not a trivial task in SDM systems, as MDG strongly influences the electrical SNR after the equalizer. In a recent work we propose an MDG and SNR estimation method using artificial neural networks (ANNs). The proposed ANN-based method processes features extracted at the receiver after digital signal processing (DSP). In this paper, we discuss the ANN-based method in detail, and validate it in an experimental 73-km 3-mode transmission link with controlled MDG and SNR. After validation, we apply the method in a case study consisting of an experimental long-haul 6-mode link. The results show that the ANN estimates both MDG and SNR with high accuracy, outperforming conventional methods.

Nonlinear equalization based on pruned artificial neural networks for 112-Gb/s SSB-PAM4 transmission over 80-km SSMF

Zhiquan Wan, Jianqiang Li, Liang Shu, Ming Luo, Xiang Li, Songnian Fu, and Kun Xu
Opt. Express 26(8) 10631-10642 (2018)

Convolutional-neural-network-based versus vision-transformer-based SNR estimation for visible light communication networks

Zhenquan Zhao, Faisal Nadeem Khan, Zeyad A. H. Qasem, Bohua Deng, Qian Li, Zhengyong Liu, and H. Y. Fu
Opt. Lett. 48(6) 1419-1422 (2023)

MIMO carrier phase recovery for carrier-asynchronous SDM-MIMO reception based on the extended Kalman filter

Kohki Shibahara, Takayuki Mizuno, and Yutaka Miyamoto
Opt. Express 29(11) 17111-17124 (2021)

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)

Fast QoT estimation method using cascaded artificial neural network for real-time path provisioning in IMDD based all-optical networks

Ryo Igarashi, Ryo Koma, Kazutaka Hara, Jun-ichi Kani, and Tomoaki Yoshida
Opt. Express 32(2) 1176-1187 (2024)