Fiber optic attenuator, also named optical attenuator, is a small device developed to reduce the power level of an optical signal. The receiver may be damaged When the optic signal arriving at the receiver is too strong. The attenuator can be used to avoid it to happen. The basic types of optical attenuators are fixed, step-wise variable, and continuously variable.

Fiber optic attenuator are commonly used in two scenarios. First, it is used to test power level margins by incrementally reducing the signal strength until the optical link fails. Second, it is installed permanently to properly match the transmitter and receiver levels.

Most of the fiber optic attenuators are used in single-mode link since the stronger laser are used for distance transmission. However, there are also multimode attenuators available.

The most popular type of attenuators are male to female, also called plug-style. These plug-style attenuators can be plugged into the receiver, then the pre-terminated cable plug into the attenuator. There are also male to female attenuators used to mount in patch panels and link two cables together.