Crosstalk-free photonic switching networks

Directional-coupler (DC) based optical switching networks can switch signals at the rate of several terabits per second. However, it suffers from an intrinsic crosstalk problem. Vertically stacking Banyan type network is a very promising structure to serve as the networks of DC-based optical switches. In this paper, we use a contention graph model to find the strictly nonblocking condition and the number of switching planes needed for rearrangeably nonblocking. We can find the routing algorithm from the node-coloring algorithm of this contention graph. We also solve the crosstalk problem of optical Benes network with a new 2×2 switching node design. By this way, we construct a rearrangeably nonblocking crosstalk-free switching network, and the routing algorithm of this new photonic switching network is the same as the traditional electronic Benes networks.