Diode-bar side-pumping of double-clad fibers

a formatted diode bar, the raw output of the diode bar is reformatted into a beam waist with a divergence, aspect ratio, and fill factor suitable for coupling into a conventional multimode fiber pigtail. The main drawbacks to formatted diode bar pump sources are cost, complexity and an inevitable tradeoff between coupling efficiency and source brightness. In this paper we describe how the Embedded Mirror Side Pumping (EMSP) technique allows the raw output of an unformatted diode bar to be used directly for side pumping double clad fiber (DCF) amplifiers. The EMSP technique allows the raw output of an unformatted diode bar to be coupled directly into the DCF inner cladding, without the same penalties in cost, complexity, coupling efficiency and loss of brightness. In particular, for applications at the 10 to 100 Watt power level and applications that require arrays of DCF amplifiers, diode bar EMSP will provide a very attractive alternative to systems based on for-matted diode bar pump sources.