Experimental investigation of a 16-dimensional modulation format for long-haul multi-core fiber transmission

We experimentally investigate a 16-dimensional modulation format applicable to multi-core fiber transmission, and demonstrate over 14,000 km transmission for a BER of 1E-3, a 55 % improvement in reach compared to DP-BPSK for the same spectral efficiency

Pilot-Aided Joint-Channel Carrier-Phase Estimation in Space-Division Multiplexed Multicore Fiber Transmission

The performance of pilot-aided joint-channel carrier-phase estimation (CPE) in space-division multiplexed multicore fiber (MCF) transmission with correlated phase noise is studied. To that end, a system model describing uncoded MCF transmission where the phase noise comprises a common laser phase noise, in addition to core- and polarization-specific phase drifts, is introduced. It is then shown that the system model can be regarded as a special case of a multidimensional random-walk phase-noise model. A pilot-aided CPE algorithm developed for this model is used to evaluate two strategies, namely joint-channel and per-channel CPE. To quantify the performance differences between the two strategies, their respective phase-noise tolerances are assessed through Monte Carlo simulations of uncoded transmission for different modulation formats, pilot overheads, laser linewidths, numbers of spatial channels, and degrees of phase-noise correlation across the channels. For 20 GBd transmission with 200 kHz combined laser linewidth and 1% pilot overhead, joint-channel CPE yields up to 3.4 dB improvement in power efficiency or 25.5% increased information rate. Moreover, through MCF transmission experiments, the system model is validated and the strategies are compared in terms of bit-error-rate performance versus transmission distance for uncoded transmission of different modulation formats. Up to 21% increase in transmission reach is observed for 1% pilot overhead through the use of joint-channel CPE

Joint Phase Tracking for Multicore Transmission with Correlated Phase Noise

Space-division multiplexed transmission over multicore fibers offers potential for joint-core processing to compensate for correlated phase noise. We review methods that take advantage of the phase-noise correlation across cores and assess their benefits in terms of transmission reach and pilot-rate requirements

Pb/s, homogeneous, single-mode, multi-core fiber systems

We discuss multi Pb/s transmission using homogeneous, single-mode, multi-core fibers. We outline the key components of a recent high capacity demonstration, the consequences of fiber properties and the potential for enhanced efficiency from spatial-super-channel transmission

Real-time, Software-Defined, GPU-Based Receiver Field Trial

We demonstrate stable real-time operation of a software-defined, GPU-based receiver over a metropolitan network. Massive parallelization is exploited for implementing direct-detection and coherent Kramers-Kronig detection in real time at 2 and 1 GBaud, respectively.Comment: Accepted for presentation at the European Conference on Optical Communications (ECOC) 202

Field Trial of a Flexible Real-time Software-defined GPU-based Optical Receiver

We introduce a flexible, software-defined real-time multi-modulation format receiver implemented on an off-the-shelf general-purpose graphics processing unit (GPU). The flexible receiver is able to process 2 GBaud 2-, 4-, 8-, and 16-ary pulse-amplitude modulation (PAM) signals as well as 1 GBaud 4-, 16- and 64-ary quadrature amplitude modulation (QAM) signals, with the latter detected using a Kramers-Kronig (KK) coherent receiver. Experimental performance evaluation is shown for back-to-back. In addition, by using the JGN high speed R&D network testbed, performance is evaluated after transmission over 91 km field-deployed optical fiber and reconfigurable optical add-drop multiplexers (ROADMs).Comment: Accepted for publication at Journal of Lightwave Technology, already available via JLT Early Access, see supplied DOI. This v2 version of the article is improved w.r.t. v1 after JLT peer-review. This article is a longer journal version of the conference paper: S.P. van der Heide, et al., Real-time, Software-Defined, GPU-Based Receiver Field Trial, ECOC 2020 paper We1E5, also via arXiv:2010.1433

Modulation and detection for multicore superchannels with correlated phase noise [Invited]

SDM fibers offer new opportunities and challenges for joint transmitter and receiver processing. We review multidimensional modulation and detection theory, describe algorithms for phase tracking and detection over spatial superchannels, and present some experimental results

High capacity transmission with few-mode fibers

We experimentally investigate high-capacity few-mode fiber transmission for short and medium-haul optical links. In separate experiments, we demonstrate C + L band transmission of 283 Tbit/s over a single 30 km span and recirculating loop transmission of 159 Tbit/s over 1045 km graded-index three mode fiber. The first experiment reached a data-rate per fiber mode within 90% of the record data-rates reported in the same transmission bands for single-mode fibers. The second experiment demonstrated the feasibility of reaching high data-rates over long distance few-mode fiber transmission, despite strong impairments due to mode-dependent loss and differential mode delay