Fiber optic attenuator is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. The basic types of optical attenuators are fixed, step-wise variable, and continuously variable. Fixed optical attenuators used in fiber optic systems may use a variety of principles for their functioning. Preferred attenuators use either doped fibers, or mis-aligned splices, since both of these are reliable and inexpensive. Inline style attenuators are incorporated into patch cables. The alternative build out style attenuator is a small male-female adapter that can be added on to other cables.
The fiber optic attenuators can be used on a more permanent basis in order to match the signal with a transmitter and receiver’s specific power levels. Commonly used attenuation range is from 1dB to 30dB.