Algorithm for raising OXC port count to meet traffic growth at minimum cost

A new optical cross-connect (OXC) configuration that yields hitless port-count expansion to meet traffic growth at minimum cost is presented. We introduce a control algorithm that uses a simple criterion for scaling up OXC port count. The scheme exploits the difference between node degree and fiber degree. Numerical experiments verify that our node configuration offers almost complete routing capability even though it uses substantially fewer wavelength-selective switches of small degree.