A path protection algorithm based on OSNR for all-optical networks with wavelength sharing limitation

In this paper we present a novel shared backup path protection algorithm for all-optical networks which considers physical layer impairments (PLI). The proposed algorithm searches for a link-disjoint backup lightpath that presents the higher optical signal-to-noise ratio (OSNR). The best-effort reliability approach is applied for searching the sharing backup paths. We used an analytical model to evaluate PLIs that considers the following impairments: gain saturation, amplified spontaneous emission (ASE) noise depletion in the optical amplifiers, crosstalk in the optical switches, four-wave mixing, polarization mode dispersion (PMD) and the chromatic dispersion in optical fibers. Moreover, we propose a strategy to evaluate the trade-off between the vulnerability ratio and the protection ratio using the dominance criteria. Our proposed algorithm outperformed three others well known algorithms in terms of vulnerability ratio and protection ratio.