Patent ID: 7389032

Claim:
A method for adjusting an intensity level of an optical signal transmitted through an optical fiber, comprising: providing a cylindrical interior wall and a plurality of cylindrical optical-fiber support members which are concentrically disposed, wherein each of the cylindrical optical-fiber support members has a diameter smaller than that of the cylindrical interior wall; and adjusting an intensity level of an optical signal by winding a number of turns of the optical fiber between the cylindrical interior wall and the plurality of cylindrical optical-fiber support members, wherein the number of turns corresponds to a desired amount of adjustment wherein a radius of each of the plurality of cylindrical optical-fiber support members is set within a range satisfying the following inequality: R 2(1+cos θ)− d<R 1(1−cos θ), wherein R 1 is a radius of a maximum turn of the optical fiber wound between the cylindrical interior wall and the plurality of cylindrical optical-fiber support members, R 2 (<R 1 ) is the radius of each of the plurality of cylindrical optical-fiber support members, and θ is an arrangement interval (angle) between adjacent ones of the plurality of cylindrical optical-fiber support members.