Transmission of a DAC-Free 1.12-Tb/s Superchannel with 6-b/s/Hz over 1000 km with Hybrid Raman-EDFA Amplification and 10 Cascaded 175-GHz Flexible ROADMs

Abstract

We investigated the performance of a 1.12-Tb/s (5x224-Gb/s PDM-16QAM) superchannel with 6-b/s/Hz, using optical prefiltering, over hybrid LongLine-SSMF link with hybrid Raman-EDFA amplification and cascaded 175-GHz ROADMs. A maximum reach of 1000-km with 10-ROADM passes was obtained employing nonlinear compensation.

Toward Terabit Autonomic Optical Networks Based on a Software Defined Adaptive/Cognitive Approach [Invited]

“…In this context, nextgeneration optical fiber transmission technologies with bit rates up to 400 Gb∕s and 1 Tb∕s are being intensively investigated [4][5][6]. Those systems may employ high-order modulation formats, spectral shaping, and densely packed multicarrier transmitters (superchannels) in order to increase overall system capacity in comparison to current 100 G technology, as demonstrated in our recent work in [4][5][6].…”

“…In this context, nextgeneration optical fiber transmission technologies with bit rates up to 400 Gb∕s and 1 Tb∕s are being intensively investigated [4][5][6]. Those systems may employ high-order modulation formats, spectral shaping, and densely packed multicarrier transmitters (superchannels) in order to increase overall system capacity in comparison to current 100 G technology, as demonstrated in our recent work in [4][5][6]. Regarding amplifier technologies, our current work in [48,49] investigates a hybrid optical amplifier obtaining a counter-propagating distributed Raman/EDFA hybrid topology and develops its respective hybrid automatic gain control loop, achieving lower noise figure levels together with spectral gain flatness for an all-amplifier dynamic operation region.…”

“…In this context, 100 Gbps optical transponders are already being deployed while the first (to the authors' best knowledge) 400 Gbps∕1 Tbps transponders have been demonstrated in field and laboratorial trials [4][5][6]. Such approaches increase the heterogeneity of the network since switching requirements can be very different from node to node.…”

Impairment mitigation in superchannels with digital backpropagation and MLSD

“…To minimize linear crosstalk penalties in multi-carrier transmissions, pulse shaping techniques to constraint modulated bandwidth have been explored, such as digital Nyquist filtering [4] and optical pre-filtering [5][6][7]. The benefits of those techniques have been experimentally assessed in long haul optical transmission systems.…”

WDM Transmission of 3×1.12-Tb/s PDM-16QAM Superchannels with 6.5-b/s/Hz in a 162.5-GHz Flexible-Grid using only Optical Spectral Shaping

“…In order to reduce channel spacing with low inter-channel interference (ICI) penalties for superchannel applications, optical spectral shaping at the transmitter has been proposed as a promising alternative [5]. Also, the employment of tight optical filtering at the transmitter together with digital post-filtering at the receiver side was used to reduce inter-symbol interference (ISI) effects and enable dense multiplexing for PDM-16QAM systems [6].…”