Patent ID: 6674953
Filing Date: 2004-01-06
Classification: G02B

Abstract:
A controllable attenuator comprising:a first collimator with an input fiber connected on one side thereof a first 45 degrees dielectric mirror positioned on the other side of said first collimator opposite to said input fiber; a second collimator arranged parallel to the first collimator with an output fiber connected on one side thereof; a second 45 degrees dielectric mirror positioned on the other side of said second collimator opposite of said output fiber; and means for attenuation positioned between the first reflection device and the second reflection device; wherein light coming from the input fiber through the first collimator, hitting the first reflection device, being reflected toward the second reflection device with attenuation effect thereof, further being reflected toward the second collimator and leaving from the output fiber, creates a light transmission path, so that a PDL thereof can be reduced to be below 0.1 dB; wherein said means includes a neutral density filter actuated to move in a direction essentially perpendicular to the light path between said first reflection device and said second reflection device; wherein said neutral density filter is actuated by a stepping motor; wherein â€ƒthe neutral density filter is seated upon a screw nut engaged with a lead screw which is coupled with the stepping motor via a silicon rubble coupler.