Reliability of 128x128 non-blocking optical cross-connects based on opto-mechanical switches for multiwavelength optical networks

In this paper the reliability performance of two 128x128 optical cross-connects OXCs based on opto-mechanical switches is considered. One of them is a non-blocking wavelength selective switch while the another is a non-blocking three stage Clos architecture. We have introduced an inherent redundancy into the Clos structure that significantly improves the reliability performance. For the both OXC structures the probability of maintenance free operation has been investigated. We have also presented our calculation results for commonly used reliability measures as MTBF (Mean Time Between Failures), MDT/year (Mean Downtime per year), and steady-state unavailability. It is shown that the OXC with the Clos architecture is better from the reliability point of view than the wavelength selective switch due to the inherent redundancy. Finally we have proposed the solutions in order to improve the reliability performances of the considered OXCs.