Abstract: A multimode optical fiber has a core that includes radially dependent dopant materials to provide a desired refractive index profile and a desired Raman gain coefficient profile. A laser diode pump laser array provides high brightness light that is launched into the fiber and is subject to maximum Raman gain along the optical axis, thereby favoring the lowest order mode of the fiber, discriminating against higher order modes and providing a high brightness, diffraction limited output. The fiber can be incorporated into oscillators, amplifiers and other optical devices.

Abstract: An image detection system includes a multimode fiber amplifier. The multimode fiber amplifier includes a core configured to receive an input image that includes a plurality of input beams spanning a range of incidence angles and to propagate at least some of the input beams as different ones of a plurality of transverse modes along the core. The multimode fiber amplifier provides an amplified image at an output facet thereof corresponding to the input image. A focal plane detector includes an array of detectors arranged to receive different portions of the amplified image.