Patent ID: 6341191
Filing Date: 2002-01-22
Classification: G02B

Abstract:
A variable attenuation type optical power attenuator, comprising:fixed and rotatable coaxial ferrules having respective optical fibers inserted therein along an optical axis of said ferrules, adjacent opposing end surfaces of said ferrules and said optical fibers being polished to provide surfaces inclined with respect to a plane perpendicular to said optical axis; an alignment sleeve receiving therein said fixed and rotatable ferrules, said rotatable ferrule being rotatable with respect to said fixed ferrule within said alignment sleeve; a fixed housing receiving said alignment sleeve, said fixed housing restricting rotation of said fixed ferrule and being provided with a first threaded portion; a rotatable housing having a first face ratchet facing said fixed housing, said rotatable housing being joined by a second threaded portion to the first threaded portion of said fixed housing for rotational and axial movements of said rotatable housing with respect to said fixed housing; a ratchet ring having a second face ratchet for engagement with said first face ratchet, said fixed housing restricting rotation of said ratchet ring, said ratchet ring being movable axially with respect to said fixed housing while being urged by a first spring toward said rotatable housing; and a second spring provided between said rotatable ferrule and said rotatable housing, whereby rotation of said rotatable housing changes the relative rotational angle of said rotatable ferrule with respect to said fixed housing so as to adjust the distance between the opposing ends of the optical fibers inserted in said fixed ferrule and said rotatable ferrule thereby adjusting the attenuation provided by the variable attenuator.