Digital fiber nonlinearity compensation:toward 1-Tb/s transport

The world is connected by a core network of long-haul optical communication systems that link countries and continents, enabling long-distance phone calls, data-center communications, and the Internet. The demands on information rates have been constantly driven up by applications such as online gaming, high-definition video, and cloud computing. All over the world, end-user connection speeds are being increased by replacing conventional digital subscriber line (DSL) and asymmetric DSL (ADSL) with fiber to the home. Clearly, the capacity of the core network must also increase proportionally. © 1991-2012 IEEE.

Intra-channel nonlinearity compensation for PM-16QAM traffic co-propagating with 28Gbaud m-ary QAM neighbours

We quantify the benefits of intra-channel nonlinear compensation in meshed optical networks, in view of network configuration, fibre design aspect, and dispersion management. We report that for a WDM optical transport network employing flexible 28Gbaud PM-mQAM transponders with no in-line dispersion compensation, intrachannel nonlinear compensation, for PM-16QAM through traffic, offers significant improvements of up to 4dB in nonlinear tolerance (Q-factor) irrespective of the co-propagating modulation format, and that this benefit is further enhanced (1.5dB) by increasing local link dispersion. For dispersion managed links, we further report that advantages of intra-channel nonlinear compensation increase with in-line dispersion compensation ratio, with 1.5dB improvements after 95% in-line dispersion compensation, compared to uncompensated transmission. © 2012 Optical Society of America.

Statistics of noise-driven coupled nonlinear oscillators:applications to systems with Kerr nonlinearity

We present exact analytical results for the statistics of nonlinear coupled oscillators under the influence of additive white noise. We suggest a perturbative approach for analysing the statistics of such systems under the action of a deterministic perturbation, based on the exact expressions for probability density functions for noise-driven oscillators. Using our perturbation technique we show that our results can be applied to studying the optical signal propagation in noisy fibres at (nearly) zero dispersion as well as to weakly nonlinear lattice models with additive noise. The approach proposed can account for a wide spectrum of physically meaningful perturbations and is applicable to the case of large noise strength. © 2005 Elsevier B.V. All rights reserved.

Nonlinearity management in fiber transmission systems with hybrid amplification

Nonlinearity management in transmission lines with periodic dispersion compensation and hybrid Raman-Erbium doped fiber amplification is studied both analytically and numerically. Different transmission/compensating fiber pairs are considered, with particular focus on the SMF/DCF case. © 2004 Elsevier B.V. All rights reserved.

Nonlinearity compensation via spectral inversion and digital back-propagation:a practical approach

We report performance enhancements enabled by pre-dispersed spectral inversion equivalent to that of ideal back-propagation, with further x2 increase in reach from multi-channel compensation, with spectral inversion employed upto 400km (from mid-link) with <1dB penalties. © 2012 OSA.

Multilevel system optimisation via nonlinearity management

Nonlinearity management is explored as a multilevel tool to obtain maximum transmission reach in a WDM system. A technique for the fast calculation of the optimal dispersion pre-compensation in systems with distributed amplification is proposed. © 2005 Optical Society of America.

Nonlinearity management in hybrid amplification systems

A theory of nonlinearity management in transmission lines with periodic dispersion compensation and hybrid Raman-EDFA amplification is developed. Different transmission/compensating fiber pairs performances are compared and the optimal amplification scheme determined for each case.

Nonlinearity management in fibre links with distributed amplification

An approach to nonlinearity management in optical transmission lines with periodic dispersion compensation and distributed Raman amplification was presented. The optimization of a three-step dispersion map with forward and backward pumped distributed amplification was examined. The optimization was performed using the analytical solution obtained under the assumption of undepleted pumps and without inclusion of double Rayleigh Scattering (DRS), and by means of a full numerical approach accounting for all important effects. It was found that both procedures led to the same final solution.

Phase-conjugated pilots for fibre nonlinearity compensation in CO-OFDM transmission

We experimentally demonstrate a novel fibre nonlinearity compensation technique for CO-OFDM based on phase-conjugated pilots (PCPs), showing that, by varying the PCP overhead a performance improvement up to 4 dB can be achieved allowing highly flexible adaptation to link characteristics.

Phase-conjugated subcarrier coding for fibre nonlinearity mitigation in CO-OFDM transmission

We demonstrate a novel subcarrier coding scheme combined with pre-EDC for fibre nonlinearity mitigation in CO-OFDM, showing that a performance improvement of 1.5 dB can be achieved in a 150 Gb/s BPSK PDM CO-OFDM transmission.

Monitoring static shape memory polymers using a fiber Bragg grating as a vector-bending sensor

We propose and demonstrate a technique for monitoring the recovery deformation of the shape-memory polymers (SMP) using a surface-attached fiber Bragg grating (FBG) as a vector-bending sensor. The proposed sensing scheme could monitor the pure bending deformation for the SMP sample. When the SMP sample undergoes concave or convex bending, the resonance wavelength of the FBG will have red-shift or blue-shift according to the tensile or compressive stress gradient along the FBG. As the results show, the bending sensitivity is around 4.07  nm/cm−1. The experimental results clearly indicate that the deformation of such an SMP sample can be effectively monitored by the attached FBG not just for the bending curvature but also the bending direction.

Localized waves in optical systems with periodic dispersion and nonlinearity management

We overview our recent developments in the theory of dispersion-managed (DM) solitons within the context of optical applications. First, we present a class of localized solutions with a period multiple to that of the standard DM soliton in the nonlinear Schrödinger equation with periodic variations of the dispersion. In the framework of a reduced ordinary differential equation-based model, we discuss the key features of these structures, such as a smaller energy compared to traditional DM solitons with the same temporal width. Next, we present new results on dissipative DM solitons, which occur in the context of mode-locked lasers. By means of numerical simulations and a reduced variational model of the complex Ginzburg-Landau equation, we analyze the influence of the different dissipative processes that take place in a laser.

Scaling the Advantages of Intra-channel Nonlinearity Compensation in Future Flexible Optical Networks

We report that, contrary to common perception, intra-channel nonlinearity compensation offers significant improvements of up to 4dB, in nonlinear tolerance (Q-factor), in a flexible traffic scenario, and further improvements with increasing local link dispersion, for an optical transport network employing flexible 28Gbaud PM-mQAM transponders.

Multi-level optimization of a fiber transmission system via nonlinearity management

Nonlinearity management is explored as a complete tool to obtain maximum transmission reach in a WDM fiber transmission system, making it possible to optimize multiple system parameters, including optimal dispersion pre-compensation, with fast simulations based on the continuous-wave approximation. © 2006 Optical Society of America.

Static, dynamic, and adaptive heterogeneity in distributed smart camera networks

We study heterogeneity among nodes in self-organizing smart camera networks, which use strategies based on social and economic knowledge to target communication activity efficiently. We compare homogeneous configurations, when cameras use the same strategy, with heterogeneous configurations, when cameras use different strategies. Our first contribution is to establish that static heterogeneity leads to new outcomes that are more efficient than those possible with homogeneity. Next, two forms of dynamic heterogeneity are investigated: nonadaptive mixed strategies and adaptive strategies, which learn online. Our second contribution is to show that mixed strategies offer Pareto efficiency consistently comparable with the most efficient static heterogeneous configurations. Since the particular configuration required for high Pareto efficiency in a scenario will not be known in advance, our third contribution is to show how decentralized online learning can lead to more efficient outcomes than the homogeneous case. In some cases, outcomes from online learning were more efficient than all other evaluated configuration types. Our fourth contribution is to show that online learning typically leads to outcomes more evenly spread over the objective space. Our results provide insight into the relationship between static, dynamic, and adaptive heterogeneity, suggesting that all have a key role in achieving efficient self-organization.