Patent ID: 7492994
Filing Date: 2009-02-17
Classification: G02B

Abstract:
1. A device, comprising: an input fiber to guide an input optical beam; a stationary reflector having a reflective surface that is partially transmissive to light, said reflector positioned to reflect a part of the input optical beam at said reflective surface as a reflected optical beam and to transmit a part of the input optical beam as a transmitted optical beam; an output fiber adjacent to said input fiber, said output fiber positioned to receive and guide the reflected optical beam as an output optical beam; an optical detector positioned to receive the transmitted optical beam and to produce a detector output; a magnetic field substantially axial to said input of said output optical fiber; a variable optical attenuator positioned in an optical path between said reflective surface and one of said input and said output fibers to attenuate light in response to a control signal; said variable optical attenuator comprising a movable shutter placed between said input or said output fiber and said stationary reflector, said movable shutter interacting with said optical beam, said movable shutter supported by a current carrying wire; said variable optical attenuator having a maximum attenuation when said shutter is in the path of said optical beam; whereby said magnetic field and a magnetic field produced by said current carrying wire interact, thereby causing a movement of said movable shutter; wherein said variable optical attenuator is positioned to attenuate the reflected optical beam, and wherein the detector output indicates a power level of the input optical beam.