Laser processing of highly reflective materials is important in current manufacturing environments. However, many types of laser technology suffer from inherent sensitivity to back-reflected light, which can cause an unstable process, disruptive automatic shutdowns, or even catastrophic failure of the laser. A new generation of fiber lasers addresses these limitations with high-performance components and a novel architecture that enables uninterrupted processing of highly reflective materials (FIGURE 1). Most multi-kilowatt fiber laser systems employ an architecture based on combining the outputs of multiple, lower-power fiber lasers using a fused-fiber combiner that could result in shortcomings in technical and economic performance. Most importantly, in the context of this article, fiber laser and combiner modules may be susceptible to instability or damage from back-reflections that occur during material processing. nLIGHT alta fiber lasers employ a novel architecture that solves these problems by housing the pump diodes and drivers in standalone pump modules, and the gain fibers in a configurable gain module that can generate >4kW of output power (FIGURE 2). The gain modul...