Mathieu Lefrancois

Nonlinear Interactions Between 10Gb/s NRZ Channels and 40Gb/s Channels with RZ-DQPSK or PSBT Format, over Low-Dispersion Fiber

RZ-DQPSK and PSBT are seen as promising modulation formats for upgrading 10Gb/s networks to 40Gb/s. We show that cross non-linear effects make the upgrade more challenging for RZ-DQPSK than for PBST over low-dispersion fibre.

Performance comparison of 40G and 100G coherent PDM-QPSK for upgrading dispersion managed legacy systems

We compare the performance of 40 G and 100 G coherent PDM-QPSK solutions for the upgrade of existing 10 G-based optical networks. This comparison is performed on the Alcatel-Lucent 1626LM commercial system.

Cross comparison of the nonlinear impairments caused by 10Gbit/s neighboring channels on a 40Gbit/s channel modulated with various formats, and over various fiber types

We evaluate the impact of lOGbit/s NRZ channels on the performance of one 40 Gbit/s PSBT, DQPSK or DPSK channel over two fiber types. DPSK and PSBT are much less affected by 10 Gbit/s neighbors than DQPSK.

Comparative Study of Crosstalk Created in 50 GHz-Spaced Wavelength Selective Switch for Various Modulation Formats at 43 Gbit/s

We investigate the tolerance of PSBT, DQPSK and RZ-DQPSK formats to in-band crosstalk at 43 Gbit/s when considering 50 GHz-spaced Wavelength Selective Switches. We show that PSBT and DQPSK exhibit the best margins versus crosstalk.

System design tool for high bit rate terrestrial transmission systems with coherent detection

Coherent detection offers the ability to compensate for linear transmission impairments such as fiber chromatic dispersion and polarization-mode dispersion in the digital domain, thereby enabling dispersion-uncompensated optical transmission for high performance and high cost effectiveness. In dispersion-uncompensated transmission systems, the statistics of optical nonlinearity induced distortions have been proven to be essentially Gaussian-distributed, and new physical models have emerged showing profound differences with respect to legacy systems based on direct detection. From such differences stems the need to adapt the design tool to capture these new propagation properties. In that respect, we propose a model for performance prediction, which is used to derive a simple yet effective feasibility parameter to be embedded in the design tool. The feasibility parameter is experimentally validated with real time product transponders, and realistic system configurations: a precision of ±0.5 dB is achieved for 40 Gb/s, 100 Gb/s and 400 Gb/s coherent channels, which represents an improvement of more than 3 dB over the design tool using the nonlinear phase shift as the criterion.

Real-time 200 Gb/s 8-QAM transmission over a 1800-km long SSMF-based system using add/drop 50 GHz-wide filters

We demonstrate error-free transmission over 1800 km with 1 dB Q2-margins using a commercially available real-time 200 Gb/s PDM-8QAM transponder (44.8 GBaud) in a super-channel with carriers spaced by 50 GHz using legacy 50GHz-mux-demux stages.

Improvement of tolerance to nonlinearities resulting from small sequence modifications in 40 Gbit/s optical transmission

Nonlinear threshold improvement has been quantified numerically and experimentally in 40 Gbit/s NRZ transmission over SMF by changing only a few penalising bits from pseudo-random sequences. This can lead to new small-overhead coding methods.

Numerical discrimination of intrachannel cross-phase modulation and intrachannel four-wave mixing and their respective effect on 40 Gbit/s transmissions

We propose a numerical method to accurately discriminate the influence of the different intrachannel nonlinear effects occurring in 40 Gbit/s optical transmissions, following an analogy with methods used to discriminate WDM interchannel effects. In contrast to other studies showing the predominance of intrachannel cross-phase modulation when low-dispersion fibers are used, in our study intrachannel four-wave mixing is the most penalizing effect in all investigated cases.

400 Gb/s Real-Time Trials on Commercial Systems for Next Generation Networks

We report the results of a field trial carrying 400-Gb/s real-time dual-carrier PDM-16QAM signals over a 550-km-long commercial system. After the examination of the propagation nonlinear noise statistics nature, we analyze the accuracy of a performance prediction model based on Gaussian nonlinear distortions on the lab replica of on-the-field conditions. Further on, we demonstrate the compatibility of 400-Gb/s real-time dual-carrier PDM-16QAM signals with legacy systems based on a 50-GHz channel grid, yielding 4 b/s/Hz of spectral efficiency over 550-km transmission. In the last part of the paper, we review recently published field trials employing real time 400 Gb/s dual-carrier PDM-16 QAM channels and discuss the potential of such transponders to further increase spectral efficiency beyond 4 b/s/Hz forming superchannels and to be configured by software according to traffic demand.

400Gb/s trials on commercial systems using real-time bit-rate-adaptive transponders for next generation networks

We review recent field trials employing real time 400Gb/s dual-carrier PDM-16 QAM channels. The results demonstrate their compliance not only with nowadays 50-GHz grid network but also with next generation flexgrid networks carrying super-channels.