High-power narrow-linewidth all-fibre amplifiers for power scaling applications

Large mode area (LMA) fibre technology has become an established means of power scaling fibre lasers and amplifiers. As the basic fibre design has become standardised, this has encouraged component manufacturers to design and build high power LMA compatible devices. This study demonstrates an example of this, by constructing a pump-power limited high-power (220 W) all-fibre amplifier based on LMA fibres and components. Such amplifiers are suitable for amplifying single frequency input signals into the 200 W regime and then potentially beam combining into the multi-kW regime. Furthermore, as higher brightness fibre-coupled pumps continue to become available this should enable further power scaling.