This is an attenuator that directly coats a metal absorption film or reflection film on the end face of the optical fiber or the glass substrate to attenuate the light energy. Commonly used evaporated metal films include: Al film, Ti film, Cr film, W film, etc. Its primary function is to control the strength of. A variable optical attenuator is a key component for wavelength division multiplexing (WDM) transmission node power equalization, optical amplifier gain flattening, multiplexing point channel balancing, and receiving node power management in fiber optic communication. A fiber optic type variable. Attenuators from VIAVI offer a complete range of power-balancing options, from fixed to variable optical attenuators in field, lab, and manufacturing environments. They are used in optical communications systems to protect sensitive receivers or to modulate signals and for engineering evaluation, testing, and system validation.