Abstract: A method for preparing optical fibers for an evanescent field coupler by forming a groove along a top surface of a substrate block, wherein the groove is formed shallower than the diameter of a stripped fiber. An optical fiber is positioned in the groove, wherein a center portion of the optical fiber is stripped of its coating. The optical fiber is glued in the groove, then polished to remove a portion of its cladding to form a coupling region, while not polishing the top surface of the substrate block. An optical signal is applied to an end of the optical fiber while loss of the optical signal is measured at the coupling region. Polishing and monitoring are repeated until a desired loss value is reached. The coupler can be added to an operating optical communication system.

Abstract: An evanescent field coupler comprising a coupler holder, a first optical fiber mounted in a first substrate block, and a second optical fiber mounted in a second substrate block. The first substrate block is compliantly mounted to the holder. Means are included for positioning the substrate blocks with respect to the other for switching and adjustment of the coupling ratio. The compliant mount elastically deforms during switching and/or alignment to facilitate accurate, repeatable switching, while maintaining the desired coupling ratio between the optical fibers.

Abstract: Signal energy in an installed optical fiber is extracted without using a physical connector, by an improved process in which the fiber is bent to within a prescribed range of angles, then controllably heated, and thereafter controllably cooled. The resulting structure exhibits relatively low permanent stress. A fiber end conventionally placed at the bend point receives unusually useful amounts of optical signal which can be routed to optical branch circuits in, for example, a building or a LAN.