Highly efficient light coupling from GaAIAs lasers into optical fibers

Abstract

A new technique is reported for highly efficient light coupling from GaAlAs lasers into step or graded index fibers. The cladding of the fiber is etched to reduce the fiber diameter to nearly the core diameter. Then the fiber end is cut and dipped in a low melting, transparent material to form a lens. This technique is reproducible and is applicable—contrary to a flame melting process—to all types of multimode fibers. We measured 80% coupling efficiency to a 20-m long, cabled graded index fiber (silica, NA = 0.13) with a glass lens on its etched end.