Patent ID: 6842570

Claim:
An optical system for providing pump light to amplify an optical signal beam, said system comprising: a tapered light guide including a first end and a second end where the first end has a narrower diameter than the second end and the tapered light guide gradually expands from the first end to the second end, said tapered light guide including a single-mode core and an aperture proximate the first end; a dual-clad amplifier fiber coupled to the second end of the tapered light guide, said amplifier fiber including a single-mode core, an inner cladding layer surrounding the single-mode core and an outer cladding layer surrounding the inner cladding layer, wherein the single-mode core of the amplifier fiber is optically coupled to the single-mode core of the tapered light guide; and a plurality of light emitters positioned proximate the aperture in the tapered light guide, said plurality of light emitters directing pump light through the aperture into the tapered light guide, wherein the pump light is reflected off of an outer surface of the tapered light guide and is directed towards the second end, and wherein the gradual increase in the diameter of the tapered light guide causes the angle of reflections of the pump light to be reduced so that the pump light is coupled into the dual-clad fiber and is contained therein by total internal reflection to amplify the signal beam in the single-mode core.