Design of optical rearrangeable 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 an optical banyan network is a novel scheme for constructing nonblocking optical multistage interconnection networks (MINs), and rearrangeable nonblocking optical MINs are feasible since they have lower complexity than their strictly nonblocking counterparts. We determine the sufficient condition for these MINs to be rearrangeable nonblocking under various crosstalk constraints. We show how the crosstalk constraint affects the design of rearrangeable nonblocking MINs and demonstrate that these networks can tolerate a stricter crosstalk constraint without increasing their hardware complexity significantly. The results will be useful in designing optical MINs with reasonable hardware cost and crosstalk level.