The evolution of passive devices in WDM networks

The development of a variety of technologies has progressed over the last ten years to meet the demands for optical bandwidth in fiber-optics networks made available by wavelength division multiplexing (WDM). These technologies will be described and compared for their ability to fulfill optical functions. The role of currently developing technologies and devices for future networks is discussed. Methods of active control of passive devices are described to compensate for system changes. The increasing demands for lower costs and functionality are the motivation toward integration, automated assembly and versatility of technology.