Abstract: A multimode fiber coupler has a structure in which a plurality of tapered pump fibers are coupled laterally to a multi-clad fiber, such as a double clad fiber (DCF). Such coupler is produced by first forming a plurality of tapered pump fibers and positioning them around the multi-clad fiber, thus forming a fiber bundle. Then, the fiber bundle is twisted and fused so that the input pump fibers converge towards a waist and then diverge from it. The diverging portions of the pump fibers may be removed from the structure. Also, at the waist, the structure may be cleaved and the portion with the converging pump fibers is then spliced with a multi-clad fiber which is similar or identical to the one in the middle of the bundle.

Abstract: A multimode fiber coupler has a structure in which a plurality of tapered pump fibers are coupled laterally to a multi-clad fiber, such as a double clad fiber (DCF). Such coupler is produced by first forming a plurality of tapered pump fibers and positioning them around the multi-clad fiber, thus forming a fiber bundle. Then, the fiber bundle is twisted and fused so that the input pump fibers converge towards a waist and then diverge from it. The diverging portions of the pump fibers may be removed from the structure. Also, at the waist, the structure may be cleaved and the portion with the converging pump fibers is then spliced with a multi-clad fiber which is similar or identical to the one in the middle of the bundle.

Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.

Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.

Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.