Design of Optical Rearrangeably Nonblocking MINs under Various Crosstalk Constraints

Optical networks suffer from the intrinsic crosstalk problem that should be overcome to make optical networks work properly. Vertical stacking of optical banyan network is a novel scheme for constructing nonblocking optical multistage interconnection networks (MINs), and rearrangeably nonblocking optical MINs are feasible since they have lower complexity than their strictly nonblocking counterparts. In this paper, we determine the sufficient condition for these MINs to be rearrangeably nonblocking under various crosstalk constraints. We show how crosstalk constraint affects the design of rearrangeably nonblocking MINs and demonstrate that these networks can tolerate a stricter crosstalk constraint without increasing their hardware complexity significantly. The results in the paper will be useful in designing the optical MINs with reasonable hardware cost and crosstalk level.