In WDM optical networks, the physical layer impairments (PLIs) and their significance depend on network type-opaque, translucent, or transparent; the reach-access, metro, or core/long-haul; the number and type of network elements-fiber, wavelengths, amplifiers, switching elements, etc.; and the type of applications-real-time, non-real time, missioncritical, etc. In transparent optical networks, PLIs incurred by non-ideal optical transmission media accumulate along an optical path, and the overall effect determines the feasibility of the lightpaths. If the received signal quality is not within the receiver sensitivity threshold, the receiver may not be able to correctly detect the optical signal and this may result in high bit-error rates. Hence, it is important to understand various PLIs and their effect on optical feasibility, analytical models, and monitoring and mitigation techniques. Introducing optical transparency in the physical layer on one hand leads to a dynamic, flexible optical layer with the possibility of adding intelligence such as optical performance monitoring, fault management, etc. On the other hand, transparency reduces the possibility of client layer interaction with the optical layer at intermediate nodes along the path. This has an impact on network design, planning, control, and management. Hence, it is important to understand the techniques that provide PLI information to the control plane protocols and that use this information efficiently to compute feasible routes and wavelengths. The purpose of this article is to provide a comprehensive survey of various PLIs, their effects, and the available modeling and mitigation techniques. We then present a comprehensive survey of various PLI-aware network design techniques, regenerator placement algorithms, routing and wavelength assignment algorithms, and PLI-aware failure recovery algorithms. Furthermore, we identify several important research issues that need to be addressed to realize dynamically reconfigurable next-generation optical networks. We also argue the need for PLI-aware control plane protocol extensions and present several interesting issues that need to be considered in order for these extensions to be deployed in real-world networks.

Physical layer impairment aware routing (PLIAR) in WDM optical networks: issues and challenges

Optical and other solitons for the fourth-order dispersive nonlinear Schrödinger equation with dual-power law nonlinearity

The nonlinear scattering effects in optical fiber occur due to inelastic-scattering of a photon to a lower energy photon. This paper describes stimulated Brillouin scattering and stimulated Raman scattering processes. Their thresholds, reduction in power penalty and applications along with comparative study of these effects are also presented.

/pdf/nonlinear-scattering-effects-in-optical-fibers-3kj53paipu.pdf

Nonlinear Scattering Effects in Optical Fibers

The group velocity dispersion (GVD) imposes severe limit on information carrying capacity of optical communication systems. By choosing appropriate pulse shape highly stable light pulses known as solitons are generated when effect of GVD is balanced by self-phase modulation (SPM). The application of solitons in communication systems opens the way to ultrahigh-speed information superhighways. Transmission speed of order of Tbit/s can be achieved if optical amplifiers are combined with WDM in soliton based communication systems.

/pdf/soliton-based-optical-communication-vp7sblnfqz.pdf

Soliton based optical communication

In this paper we have reported soliton solution of one dimensional modified complex Ginzburg Landau equation. The parametric region where such soliton solution is possible is also identified.

/pdf/temporal-solitons-of-modified-complex-ginzberg-landau-gk5gtng33k.pdf

Temporal Solitons of Modified Complex Ginzberg Landau Equation

The nonlinear effects in optical fiber occur either due to intensity dependence of refractive index of the medium or due to inelastic-scattering phenomenon. This paper describes various types of nonlinear effects based on first effect such as self-phase modulation, cross-phase modulation and four-wave mixing. Their thresholds, managements and applications are also discussed; and comparative study of these effects is presented.

/pdf/nonlinear-effects-in-optical-fibers-origin-management-and-3rps8k80kl.pdf

Sunil Pratap Singh

Papers

Nonlinear Effects in Optical Fibers: Origin, Management and Applications

Nonlinear Scattering Effects in Optical Fibers

Soliton based optical communication

Gain optimization of an erbium-doped fiber amplifier and two-stage gain-flattened EDFA with 45 nm flat bandwidth in the L-band

Crosstalk reduction in WDM systems using hybrid amplification technique