Opto-electronics has played a key role in long-distance cabled communications by offering high-performance, easy-to-use, compact devices at acceptable cost. Spreading throughout metropolitan networks and access networks and more generally facing the increasing demand for less expensive and wider bandwidth call for new functionalities and improved technologies. This evolution covers all fibre network components and their management: signal propagation and processing along fiber, optoelectronic interfaces, electronic processing, . . . Issues, progress and perspectives of devices as enablers of capacity, flexibility and cost reduction are addressed.