Retro-reflective alignment technique for fiber optical connectors

Abstract

An apparatus and method provides an optically aligned connector for at le one optical fiber. A connector plate is machined with one flat surface which is placed in an abutting relationship on an optically flat mirror surface. A quarter pitch graded refractive index lens is inserted in a hole through the connector plate and bonded in place. The hole through the connector need not be precision bored nor is the fit between the lens and hole critical since the optical alignment is not dependent on these fittings but rather depends upon the abutting relationship of the flat abutting surface and the surface of the mirror. An optically excited fiber is brought to the close proximity of the lens and suitably micropositioned to a location where a maximum light intensity is monitored by a detector optically coupled to the excited fiber. When the fiber is positioned so that a maximum reflected intensity is monitored it is secured in place by, for example, a UV cureable adhesive. Mechanically indexing mating connector plates assure that an optical alignment from one fiber through its lens to another lens and onto another fiber is created. Multiple optical couplings between several pairs of fiber-lenses can simultaneously be created between a pair of appropriately designed connector plates. Optionally, appropriately machined collars held between single or multifibered connector plates are filled with an acceptable index matching fluid to assure suitable optical coupling.