Large-capacity strictly nonblocking optical cross-connects based on microelectrooptomechanical systems (MEOMS) switch matrices: Reliability performance analysis

In this paper, the reliability performance of 128 x 128 optical cross-conne cts (OXCs) based on microelectrooptomechanical systems (MEOMS) switch matri ces is considered. First, we compare a strictly nonblocking wavelength sele ctive switch with a strictly nonblocking three-stage Clos architecture. The probability of maintenance of free operation has been investigated for bot h OXC structures. We present our calculation results for such commonly used reliability measures as mean time between failures (MTBF), mean downtime ( MDT) per year, and steady-state unavailability. It is shown that the reliab ility performances of the considered OXCs are far from that requested. In t his paper, we also investigate possibilities of improving the reliability p erformance of the considered OXCs by introducing shared redundancy of the M EOMS matrices. We propose two different protection schemes: one for the wav elength selective switch [1] and another for the three-stage Clos architect ure. It is shown that the proposed protection schemes significantly improve the reliability performance for both cases. Finally, we compare the perfor mance of the all-optical version of the OXC based on MEOMS matrices with th e optoelectronic version of the OXC based on electronic cross-point switch matrices. It is shown that from a reliability viewpoint, the optical cross- connect based on MEOMS matrices is better than that with electrical cross-p oint switches. The influence of capacity expansion on the system reliabilit y is discussed.