Fiber optic attenuator is a passive device used to reduce the power level of an optical signal because too much light can overload a fiber optic receiver and degrade the bit error ratio (BER). To achieve the best BER, the light power must be reduced by using fiber optic attenuator. Generally, the optical attenuators are used in single-mode long-haul applications to prevent optical overload at the receiver.Optical attenuator reduces signal power by absorbing the light, like sunglasses absorb the extra light energy. Or by scattering the light like an air gap. Fiber optic attenuators are commonly used in two scenarios:
