Patent ID: 6363203
Filing Date: 2002-03-26
Classification: G02B

Abstract:
A variable fiber optic attenuator comprisinga first, movable fiber including a first endface; a second, fixed fiber including a first enface; a fixed substrate for supporting said first and second fibers such that the first endfaces of each fiber are disposed so as to provide optical coupling therebetween, said substrate defined as having a top surface and further comprising a cavity disposed underneath an end portion of said first, moveable fiber proximate to said first endface of said first, moveable fiber; and an adjustable arrangement for physically moving said end portion of said first fiber into said cavity of said fixed substrate and introducing attenuation in an optical signal by decreasing the optical coupling between said first endface of said first, moveable fiber and said first endface of said second, fixed fiber, said adjustable arrangement comprising a permalloy sleeve disposed to surround the end portion of the first, moveable fiber; electromagnetic plates disposed above and below said sleeve; and an electromagnetic source for varying the magnetic field applied to said plates wherein in the presence of a magnetic field said permalloy sleeve is drawn into the substrate cavity and said first fiber endface moves upward relative to the endface of the second, fixed optical fiber in the presence of the magnetic field to achieve optical attenuation.