A method and apparatus for optimizing optical transport using a software defined network (SDN) controller are disclosed herein. The SDN controller may define a margin optimization function based on at least one optical system performance metric. The function may include at least one related initiation criterion. Further, the SDN controller may collect at least one measurement for the performance metric. The measurement may include an assessment of deployed carriers not carrying client data. The SDN controller may determine whether the initiation criterion is met based on at least one collected measurement. The SDN controller may select a system margin optimization mechanism and define a system margin optimization threshold criterion on a condition that the initiation criterion is met. The SDN controller may determine whether the optimization threshold criterion is met. The SDN controller may implement one or more optimization events on a condition that the optimization threshold criterion is met.