System and method for introducing pump radiation into high-power fiber laser and amplifier

Light amplifier including an active optical fiber, arranged such that a plurality of fiber sections thereof are aligned and closely packed along a substantially flat plane, thereby defining a light pumping region, and a light introducer having an entry surface and a substantially flat exit surface, the substantially flat exit surface being coupled with the light pumping region, wherein the light enters the active fiber at the light pumping region, through the light introducer, and wherein the device amplifies the light by exciting the active constituents of the active optical fiber.