Optical physical layer SDN [invited]

Optical system management software has been migrating toward software-defined networking (SDN) methods and interfaces. The increased programmability of SDN promises greater flexibility, dynamic operation, and multivendor compatibility for optical systems. However, physical layer control systems are complicated by transmission engineering requirements, including quality of transmission, optical power stability, and multidomain service guarantees. These challenges and recent commercial and research efforts to address them are examined.