Attenuators are usually made from simple networks. between different resistances forms adjustable stepped attenuators and continuously adjustable ones using. For higher frequencies precisely matched low networks are used. Fixed attenuators in circuits are used to lower voltage, power, and to improve.
[pdf] Fiber optical adjustable attenuator is a product which is dedicated manually to adjust the attenuation of fiber optical path. Tensile Load The temperature measurement environment is 23℃. MVOA features low insertion oss, good resolution, high stability and good reliability.
[pdf] 
