Magnetically tunable optical attenuator and method of attenuating signals

Abstract

A variable attenuator device is disclosed that may be magnetically and latchably controlled such that it does not require a continuous power supply to maintain a particular loss level. The variable attenuator comprises two optical components disposed in spaced apart relation to define a gap between them and a magnetic shutter positioned within the gap. The shutter is movable, due to its magnetic properties, from a first position to at least a second position, where the second position may be within, partially within, or outside of the gap. A mechanism is provided for magnetizing or actuating the shutter to cause it to move from the first position to the at least second position. When the shutter is in the first position, it causes a certain amount of attenuation in the signal being transmitted between the two optical components, and when it moves to the at least second position, a different amount of attenuation is caused, such that movement of the shutter causes a variation in the attenuation. With this attenuator, the variation in attenuation may be achieved via coupling loss while the optical components (e.g., mating fibers), are maintained in a fixed position, thereby avoiding difficulties associated with fiber movement.