Patent ID: 7665901

Claim:
An adapter unit for enabling isolated physical coupling with less than 1 dB optical insertion loss to complete a communication link between end faces of opposing first and second ferrule tipped terminals each including central optical fiber cores, the end faces being spaced apart by a predetermined distance including a transition section along a longitudinal central optical communication axis and the adapter unit comprising: a housing body encompassing the transition section at an intermediate region along the longitudinal central optical communication axis; a sleeve holder disposed in the housing body in a position to span the longitudinal transition section, the sleeve holder including a central aperture about the central axis and being divided transversely in an intermediate region along its length relative to the central optical communication axis; a sleeve disposed within the central aperture in the sleeve holder and extending therethrough, the sleeve comprising a semi-rigid cylindrical element substantially spanning the length of the sleeve holder, and including a longitudinal separation, and being concentric with the central optical communication axis and defining opposite end receptacles sized for receiving the ferrule tipped terminals of optical fiber connectors; a fiber optic stub disposed within the sleeve between the opposite end receptacles, the stub including polished end faces defining the opposite ends thereof for engagement with the opposed end faces of ferrule tipped terminals inserted and retained in the opposite end receptacles of the sleeve, the stub further including a length of longitudinally continuous central optical fiber core within an encompassing material, the core being in alignment with the optical communication axis and configured to define the transition section; the end faces of the stub being configured to closely abut the opposing end faces of ferrule tipped terminals positioned in the sleeve and providing substantial optical continuity along the central optical communication axis, and wherein the inner diameter of the sleeve is dimensioned to maintain transverse misalignment of the central optical fiber cores relative to the central optical communication axis, within 1 micron, and wherein the transition section between the central optical fiber cores in the ferrule tipped terminals and the central optical fiber core of the stub is adiabatic in character.