Study on the cascadability of a SOA-assisted Sagnac switch pair

The ability of the SOA-assisted Sagnac switch to be cascaded in a pair scheme where the output from the transmission port drives directly the subsequent control terminal is investigated and demonstrated. For this purpose an efficient model that simulates the behavior of the SOA employed in each one of these interferometric arrangements is suitably applied to describe their concatenated setup. By conducting an extensive theoretical treatment the impact of the involved critical operational parameters on the defined quality metrics is thoroughly analyzed and assessed enabling to provide useful design rules for their proper selection and the achievement of enhanced performance. The two switches in tandem are a replica of each other if the leading one is driven as well as serially triggers its trailing counterpart with the proper amount of energy so that both SOAs are biased around the same saturation point. In this manner the formed chain is practically realizable and its contrast ratio can be optimized by means of the second module it comprises of. The outcome of this work can facilitate the implementation of larger, multistage switch fabrics and combinatorial circuits of non-trivial logical functionality in which this kind of interconnected architecture is the basic building block.