The last two years has seen rapid development in the field of fiber lasers. In particular, reported output powers have dramatically increased by several orders of magnitude, from 10W to 1KW. While the generic benefits of fiber lasers are well known (e.g. efficiency and compactness), the power scaling of these devices does present challenges that need to be addressed before the deployment of reliable systems is achieved. In this contribution, we address optical branching component requirements for High Power Fiber Lasers (HPFLs). Monolithic, fused fiber devices are clearly the component of choice to enable fully integrated, reliable HPFLs. The required components can be classed in two distinct groups. The first group are single mode devices whose function relies on cladding coupling based on fused biconical tapers and these include tap couplers, wavelength combiners/splitters, and filters. The second group includes multi-mode devices, primarily used for the power combining of multi-mode pump diodes. We describe the latest developments in
state-of-the-art fused fiber components for HPFL systems, including the use of low ratio tap couplers for optical feedback and control in fully integrated fiber laser systems of up to 100W.