Open AccessOptical performance monitoring using digital coherent receivers and convolutional neural networks
Author(s) -
Hyung Joon Cho,
Siddharth Varughese,
Daniel Lippiatt,
Richard DeSalvo,
Sorin Tibuleac,
Stephen E. Ralph
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.406294
Subject(s) - demodulation , computer science , modulation (music) , phase shift keying , bit error rate , quadrature amplitude modulation , polarization division multiplexing , convolutional neural network , optics , signal to noise ratio (imaging) , convolutional code , signal processing , electronic engineering , telecommunications , algorithm , artificial intelligence , physics , decoding methods , channel (broadcasting) , radar , acoustics , engineering
We experimentally demonstrate accurate modulation format identification, optical signal to noise ratio (OSNR) estimation, and bit error ratio (BER) estimation of optical signals for wavelength division multiplexed optical communication systems using convolutional neural networks (CNN). We assess the benefits and challenges of extracting information at two distinct points within the demodulation process: immediately after timing recovery and immediately prior to symbol unmapping. For the former, we use 3D Stokes-space based signal representations. For the latter, we use conventional I-Q constellation images created using demodulated symbols. We demonstrate these methods on simulated and experimental dual-polarized waveforms for 32-GBaud QPSK, 8QAM, 16QAM, and 32QAM. Our results show that CNN extracts distinct and learnable features at both the early stage of demodulation where the information can be used to optimize subsequent stages and near the end of demodulation where the constellation images are readily available. Modulation format identification is demonstrated with >99.8% accuracy, OSNR estimation with <0.5 dB average discrepancy and BER estimation with percentage error of <25%.