Oriol Bertran-Pardo

Throughput comparison between 50-GHz and 37.5-GHz grid transparent networks [Invited]

With the introduction of Nyquist pulse shaping, it is possible to transmit a channel in a spectral window close to its baud rate. To increase the overall network spectral efficiency, the most promising solution seems to be the reduction of the channel spacing. Standardization bodies have proposed a flexible grid with 12.5 GHz of granularity. Hence, 100-Gb/s signals can be transported in a 37.5-GHz grid network. While a 37.5-GHz channel spacing brings an ideal extra-throughput of 33% compared to a 50-GHz spacing, this value ignores filtering-induced impairments occurring when a narrower channel spacing is adopted. In this paper, we numerically investigate the filtering penalty stemming from optical filters and its implications on the extra-throughput provided by 37.5- versus 50-GHz grid wavelength division multiplexing (WDM) networks for two different networks with two different traffic distributions. We show fully transparent network scenarios where the ideal 33% extra-throughput of 37.5-GHz channel spacing is drastically reduced or even vanishes because of filtering penalties.

Spectral engineering technique to mitigate 37.5-GHz filter-cascade penalty with real-time 32-GBaud PDM-16QAM

We investigate the potential of spectral engineering to mitigate the penalties on 32-Gbaud 256-Gb/s PDM-16QAM channels passing through the deployed cascade of 37.5-GHz wide filters in case of wavelength detuning and real-time coherent detection.

Monolithic Integrated InP Transmitters Using Switching of Prefixed Optical Phases

Recent progresses on monolithic InP integration are presented for achieving high-performance transmitters for cost-sensitive metropolitan networks. We demonstrate the generation of advanced modulation format using two types of integrated transmitters with prefixed optical phases. Complex modulation formats are generated with constellations exploiting the whole complex plane such as BPSK, quadrature phase-shift keying, N-QIM, and 2ASK-2PSK modulation. We achieve data rate up to 224 Gb/s using 2ASK-2PSK modulation with polarization division multiplexing. Finally, we assess its suitability for metropolitan networks with a large number of cascaded nodes.

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.

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.

400Gb/s Real-time Trials on Commercial Systems Using 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.

Long-haul 100Gb/s coherent transmission experiments

In this paper, we highlight the potential of Coherent PDM-QPSK format for next-generation 100Gb/s transmission systems, through a record transmission experiment of 16.4Tb/s over 2550km, and in-depth experimental analyses of tolerance to joint PMD and non-linear effects, as well as robustness to typical constraints of terrestrial optical networks.