1 specifies which devices fall into this category. The active devices described in this chapter include variable optical attenuators, tunable optical filters, dynamic gain equalizers, optical add/drop multiplexers, polarization controllers, and dispersion compensators. Many types of. Active Optical Components are used to manipulate light through a variety of electrical methods, including adaptive reflection, variable diffusion, or tunable focusing. Topics include advancements in adaptive optics, which adjust mirrors or lenses in real-time to compensate for distortions caused by atmospheric. Optical devices are optoelectronic components used in optical communication that perform various functions based on the photoelectric conversion effect. Common optical passive components in optical communications include: fiber optic connectors, fiber optic couplers. In the field of optical communications, active devices are components that can actively generate or amplify optical signals, such as laser diodes (LDs) or photodetectors (PDs).