Abstract

Time–frequency packing (TFP) transmission provides the highest achievable spectral efficiency with a constrained symbol alphabet and detector complexity. In this paper, the application of the TFP technique to fiber-optic systems is investigated and experimentally demonstrated. The main theoretical aspects, design guidelines, and implementation issues are discussed, focusing on those aspects which are peculiar to TFP systems. In particular, adaptive compensation of propagation impairments, matched filtering, and maximum a posteriori probability detection are obtained by a combination of a two-dimensional equalizer and four eight-state parallel Bahl–Cocke–Jelinek–Raviv (BCJR) detectors. A novel algorithm that ensures adaptive equalization, channel estimation, and a proper distribution of tasks between the equalizer and BCJR detectors is proposed. A set of irregular low-density parity-check codes with different rates is designed to operate at low error rates and approach the spectral efficiency limit achievable by TFP at different signal-to-noise ratios. An experimental demonstration of the designed system is finally provided with five dual-polarization QPSK-modulated optical carriers, densely packed in a 100-GHz bandwidth, employing a recirculating loop to test the performance of the system at different transmission distances.

© 2015 IEEE

Sub-Nyquist field trial using time frequency packed DP-QPSK super-channel within fixed ITU-T grid

L. Potì, G. Meloni, G. Berrettini, F. Fresi, T. Foggi, M. Secondini, L. Giorgi, F. Cavaliere, S. Hackett, A. Petronio, P. Nibbs, R. Forgan, A. Leong, R. Masciulli, and C. Pfander
Opt. Express 23(12) 16196-16208 (2015)

Suppression of Fiber Nonlinearities and PMD in Coded-Modulation Schemes With Coherent Detection by Using Turbo Equalization

Ivan B. Djordjevic, Lyubomir L. Minkov, Lei Xu, and Ting Wang
J. Opt. Commun. Netw. 1(6) 555-564 (2009)

Nonlinear BCJR equalizer for suppression of intrachannel nonlinearities in 40 Gb/s optical communications systems

Ivan B. Djordjevic and Bane Vasic
Opt. Express 14(11) 4625-4635 (2006)

Achievable information rates calculation for optical OFDM few-mode fiber long-haul transmission systems

Changyu Lin, Ivan B. Djordjevic, and Ding Zou
Opt. Express 23(13) 16846-16856 (2015)

Nonlinear-frequency-packing nonlinear frequency division multiplexing transmission

Xulun Zhang, Peng Sun, Lixia Xi, Zibo Zheng, Shucheng Du, Jiacheng Wei, Yue Wu, and Xiaoguang Zhang
Opt. Express 28(10) 15360-15375 (2020)