A method and system of determining a new path through an optical network from a source node to a destination node when a link in an original path fails are disclosed. When a fault on a link is detected, adjoint weights are assigned to each operational link for each node on the original path. A connection cost is determined for each node based on the adjoint weights of the links connected to the node. A new path through the optical network is determined based at least in part on the adjoint weights and the connection costs.