Based on the development trend of network service and the development status of all-optical network, this
paper analyzes the architecture and key feature of all-optical network, and proposes the future development direction of
all-optical network, including automation, intelligence, high reliability and metro extension. At the same time, the
basic key technologies supporting the evolution of all-optical network are studied, including optical-layer scheduling,
optical-layer digitalization, and electrical-layer scheduling. Optical-electrical collaborative operation can fully meet the
network requirements of low latency, large bandwidth and high reliability. With the rapid and significant reduction of
WSS cost, ROADM will gradually evolve from the backbone network to the metro edge network, supporting the wide
deployment of all-optical network.