Common fiber optic attenuators are fixed and adjustable. for achieving a suitable signal level for a data receiver in a telecom system. Also, by preventing overloading, attenuators can increase the lifespan of network. Optical attenuators are passive components used to reduce optical signal power to a controlled level within a fiber optic system. Their function is purely to introduce controlled loss, expressed in decibels. Optical attenuators achieve the desired attenuation in optical fiber links in three different principles, which relatively are gap-loss principle, absorptive principle, and reflective principle.