Abstract

Efficient coupling of light into single-mode fibers requires end fire coupling, or evanescent field fiber couplers. For multimode fibers, efficient (≫50%) coupling has only been achieved through end fire coupling. Coupling into multimode fibers is important for pumping of double-cladding active fibers used in high-power, diode-array-pumped amplifiers, super fluorescent sources, and lasers.^1–3 End fire coupling into the inner cladding has two important drawbacks: a bulk dichroic beam-splitter is required, and the total area avaialble for pump light injection is limited by the fiber facet size.

© 1996 Optical Society of America