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We study the techno-economics of submarine systems constrained by a fixed electrical power supply. We show significant cost savings for high-capacity submarine systems using massive space-division multiplexing (SDM), even without assuming any savings from SDM-specific subsystem integration. Systems with about 100 parallel optical paths, e.g., $\sim$ 50 fiber pairs are shown to provide minimum cost/bit, operating at reduced spectral efficiencies and deep within the linear regime. While advanced nonlinearity-optimized fibers and digital nonlinearity compensation schemes provide little to no gain in such systems, SDM integration of amplifiers and transponders is shown to be a source for significant additional cost savings. We further examine the permissible cost premium for multicore fibers in such massively parallel systems and revisit various design tradeoffs for optical amplifiers, showing that a reduced noise figure can be traded for better power conversion efficiency. We also evaluate potential gains from increasing the available electrical supply power and discuss reliability aspects of massively parallel submarine systems.

We report the transmission of probabilistically shaped (PS) 64-ary quadrature amplitude modulation (QAM) at 7.46 b/s/Hz over a 5523-km in-service trans-Atlantic fiber-optic cable that consists of 65–89-km spans of Erbium-doped fiber amplifier only amplified fiber. Using a looped-back system configuration, we achieve 5.68 b/s/Hz over a trans-Pacific-equivalent distance of 11 046 km. Net spectral efficiencies are increased by 18% and 80% by using PS, at 5523 km and 11 046 km, respectively, compared to uniform square QAM. Throughout our experiments, we pay particular attention that our claims are backed by implementable forward error correction schemes. In addition, we demonstrate real-time coherent transmission of single-carrier 200 and 250-Gb/s uniform 8-QAM and 16-QAM at 4 b/s/Hz over the 5523-km cable.

We show significant cost savings for high-capacity submarine systems using massive spacedivision multiplexing (SDM) for a fixed electrical power supply. Advanced submarine fiber, low-noise amplification, and digital nonlinearity compensation are shown to provide little benefit for such systems.

We transmitted probabilistically shaped 64-QAM at 7.46 b/s/Hz over a 5,523-km inservice EDFA-only amplified trans-Atlantic cable (5.68 b/s/Hz over a looped-back 11,046 km). Using real-time processing we achieve single-carrier 250-Gb/s 16-QAM at 4 b/s/Hz.

In the last years, the migration from 10 to 40/100 Gbps networks has been proposed as a solution to increase the capacity of transparent optical networks. Initially, the replacement of 10 Gbps legacy equipment was considered. Nowadays, some works point out that the deployment of mixed line rate (MLR) networks, where 10 Gbps and higher bit rate Gbps channels share the same fiber, could be more cost effective than the total replacement of 10 Gbps systems. In this paper, we investigate the planning of 10/40 Gbps MLR networks using the ITU 50 GHz grid, considering nonlinear interferences between 10 and 40 Gbps channels, which degrade the quality of transmission. This approach is novel in the literature. In addition, we conduct a set of tests normalizing the length of fiber links, to observe the trends in MLR planning for different network sizes.

A vertical perspective, ranging from management and routing to physical layer options, concerning dynamic network monitoring and compensation of impairments (M&C), is given. Feasibility, reliability, and performance improvements on reconfigurable transparent networks are expected to arise from the consolidated assessment of network management and control specifications, as a more accurate evaluation of available M&C techniques. In the network layer, physical parameters aware algorithms are foreseen to pursue reliable network performance. In the physical layer, some new M&C methods were developed and rating of the state-of-the-art reported in literature is given. Optical monitoring implementation and viability is discussed. Publicado

Nowadays in optical networks there is a trend line to extend the maximum transmission distance. Several techniques are known; however, the simplest one is to increase the signal power in the optical fiber. The task of minimizing the number of inline amplifiers in order to increase the deployed system’s cost effectiveness leads to increasing the signal power. The only problem is the nonlinear behavior of the optical fiber which limits the signal power to be inserted into the optical fibers. In this paper, we present a model to calculate analytically the signal quality deterioration due to nonlinear effects at the receiver point. As a result, we give the exact value of the optimal signal power at the transmitter point or at the output of the inline amplifiers for 10 Gbit/s wavelength division multiplexed (WDM) systems.

The paper provides a comprehensive overview of security issues in state-of-the-art optical networks. It identifies and describes the main vulnerabilities of today’s and future networks and outlines potential methods of attack which could exploit these vulnerabilities.

The ever increasing bandwidth-hungry applications trigger an unexpected transformation in telecommunication networks. This influences all network layers, with the highest impact in layer zero, L0.

Over 1 Tbit/s/port wide-colored optical packet switching technologies are described. We demonstrate transparent operation of an optical packet switch system for various format and bit-rate, and presents its energy efficiency and network scalability.

We investigate the performance of NRZ-OOK, NRZ-DPSK, NRZ-DQPSK, NRZ-8PSK and NRZ- 16-QAM modulation and their influence to an optical packet switched systems (OPS) performance. The aim was to demonstrate that OPS systems can be spectrally efficient.

Using a transmission loop, we show the maximum number of cascaded conventional- EDFAs is gain-transient limited for packet transmission and demonstrate error-free, noise limited packet transmission across 44 transient-suppressed EDFA's without active gain-transient control or regeneration.

We investigate the scalability of a SOA based optical switch for optical packet-switched system. By extensive simulations, based on the expected switch parameters, a consecutive switch limit of 14 or 9 is demonstrated.

By extensive simulations we investigate the influence of different modulation formats on the performance of a 640Gbit/s/port optical packet switching system.

In both metropolitan optical networks (MON) and long haul optical networks (LHON) the signal quality is often influenced by the physical impairments, therefore a proper impairment based routing decision is needed. In this paper we propose new routing and wavelength assignment (RWA) methods where the control plane has influence on the signal power of the Wavelength Division Multiplexed (WDM) channels. Nowadays in nearly all kinds of reconfigurable optical add-drop multiplexers (ROADM) the signal power can be tuned via variable optical attenuators (VOA) from the control plane. We give the exact integer linear programming (ILP) formulation of the method for both single and multilayer networks. In the first case we assume that no signal regeneration is allowed along the path, while in the more complex multilayer case 3R signal regeneration, grooming and wavelength conversion can all be done in the electronic layer. The proposed algorithm can be used in existing WDM optical networks where the nodes support signal power tuning. The algorithm finds the global optimum, if it exists, for a certain network topology, physical constraints and demand set.

In both, metropolitan optical networks (MON) and long haul optical networks (LHON) the signal quality is often influenced by the physical impairments, therefore proper impairment constrained routing decisions are needed. In this paper we propose two new approaches that jointly perform, on the one hand, routing and wavelength assignment (RWA) and, on the other hand, either tuning the signal power of certain wavelength division multiplexed (WDM) channels or grooming the traffic of some WDM channels in nodes that are grooming capable. We evaluate the proposed optimization methods for both, single and multilayer networks. In the first case we assume that no signal regeneration is allowed along the path, only re-amplification, while in the more complex two-layer case we assume grooming in the electronic layer that implicitly performs 3R signal regeneration and wavelength conversion as well.

In both, metropolitan optical networks (MON) and long haul optical networks (LHON) the signal quality is often influenced by the physical impairments, therefore a proper impairment based routing decision is needed. In the absence of all-optical 3R regenerators, the quality of transmission has a strong impact on the feasibility of all-optical transmission. It is assumed that signal regeneration can be done only in electrical layer. Once the signal is in electrical layer there are some features supported e.g. the traffic grooming. We show that by taking into account both, the physical impairments characterized by the Q-factor, as we propose, and the features of the electrical layer, will have a strong impact onto the routing that is based on impairment constraints.

Physical impairments in both metropolitan optical networks (MON) and long haul optical networks (LHON) often influence the signal quality, therefore a proper routing decision is needed. In this paper we investigate how to design traffic grooming optical virtual private networks (oVPN), over WDM (CWDM or DWDM) networks, while obeying the properties of the physical layer. Although we obtain these limiting properties using simulations, actual measurements can be used as well. Optimization was achieved by integer linear programming (ILP) (T. Cinkler, February 2001), where the physical limitations are represented using a set of new variables and constraints. Since the problem is NP hard, we decompose it using heuristics into multiple, less complex, sub-problems. The proposed method is illustrated in a case study.