A Novel Pump Combiner for High Power Fiber Lasers

摘要

The problem of coupling multimode radiation into double clad optical fiber lasers becomes of increasing significance with demands for increased laser output power. There are, at present, several techniques for coupling of radiation into the double clad fiber. These include the tapered bundles developed by OFS Optics in which six fibers surround a central fiber. This bundle is then tapered down to match the diameter of a double clad fiber. The central fiber can be a single mode fiber that can serve as a seed source in an amplifier configuration, or seven pump fibers can be used to pump the gain fiber. These devices can be placed at intervals along the gain fiber for increased power. Another technique "notches" the double clad fiber so that external diode radiation can be sent into the double clad fiber core. Another, and perhaps the most successful in terms of commercial exploitation, is the side coupling technique developed by IPG Photonics. In this case the fiber connected diode (or combined diode) outputs are tapered and fused around the double clad fiber so that light is efficiently coupled into the first cladding. Yet another technique has been proposed as the LG Wave Technique of Southampton. In this, technique, performs of individual double clad fibers and diode-pump fibers are drawn together in a large number of configurations such that the pump light can ultimately be transferred into the first cladding of the double clad fibers.