Reproducible standard for aligning fiber optic connectors which employ

Abstract

A method of fabricating an optically aligned coupling between an optical fiber and a connector having a precision-bored bushing guarantees proper light beam collimation. Graded refractive index rod lenses are coupled to the optical fiber by an installation procedure having a readily-reproducible measurement standard. Calibrating an alignment fixture calls for the inserting of a fused quartz right cylinder having a diameter to allow a snug fitting in the precision-bored bushing. The cylinder has an integral axially exposed mirrored face for reflecting the beam to create a calibration autocollimation with a beam from a laser projected through and in parallel with the axis of the precision-bored bushing. Disposing a mirror surface separated from and perpendicular to the axis of the precision-bored bushing allows the reflection of the projected beam back over its own path to result in autocollimation of the projected and reflected beams. Inserting a close fitting graded refractive index lens into an alignment ferrule that goes into the precision-bored bushing and exciting the optical fiber by a light source permits the positioning of the excited optical fiber on an axially exposed surface of the graded refractive index lens. Next, the light intensity reflected through the graded refractive index lens and into the optical fiber from the mirror surface is monitored and, when the monitored light is maximum, the fiber is secured in place on the surface of the graded refractive index lens to assure the optically aligned coupling.