Abstract: A variable attenuator includes a rotatable actuator and cam arrangement arranged to vary a length of an air gap between ends of fibers in a transmission line. The cam arrangement includes a cylindrically shaped cam member having an end surface cut to fit a curve representing normalized attenuation-to-gap-length data, the cam follower(s) being fitted in a sliding member that holds the end of the optical fiber and moves it relative to a fixed end of another fiber connector member. The cam surface includes multiple identical cam surface sections extending less than 180° around the cam to define movement of the cam follower(s) and the sliding member between a maximum position and a minimum position.