WDM system and optical device: new evolution and new requirements

Based on introduction of WDM evolution and technology trend, the requirements to the optical devices of next generation WDM systems are analyzed. The requirements are focused on intelligence and low cost. Moreover, the evolution of several important optical devices is discussed. The low cost dynamic optical devices will play a important role in the next generation WDM system. It will be a main developing direction for optical devices applied in WDM systems.