Static lightpath establishment with transmission impairments consideration in WDM all-optical networks

Abstract

Providing ultra high-speed end-to-end connectivity in core optical networks while satisfying the requirements for quality of service is a topic of intense research. In an optical network, a connection is set up to carry a data signal via an all-optical channel (lightpath) from its source to destination nodes. The analog nature of the signal transmission through the network links and nodes leads to signal quality degradation due to impairments accumulation. Such degradation should be taken into account when considering the Routing and Wavelength Assignment (RWA) problem. Most of preceding studies carried out on RWA neglect the impact of the physical layer impairments. In this paper, three physical layer impairment aware RWA algorithms are developed. We explicitly consider the effect of four physical layer impairments namely Chromatic Dispersion (CD), Polarization Mode Dispersion (PMD), Optical Signal to Noise Ratio (OSNR) and Nonlinear Phase Shift (φ Ν ι). Taking into account physical impairments when solving the RWA problem intuitively should affect the computed solution: the selection of a suitable path and suitable wavelength may fail to meet the minimum transmission requirement. To the best of our knowledge, this is the first attempt to include, simultaneously, the four aforementioned transmission impairments when dealing with the RWA problem. We here propose a function that computes the Q-factor based on Eye-Opening Penalties (EOP) instead of using variances. This should lead to a better Bit Error Rate (BER) estimation. Few studies considered EOP in the last years when dealing with such a problem. The performance of the proposed algorithms is demonstrated to be promising through illustrative numerical examples.