Single mode high power fiber laser system

摘要

A high power single mode fiber laser system has a monolithic active fiber configured with a double bottleneck-shaped multimode (MM) core which is capable of supporting substantially only a fundamental mode at a given wavelength. The core has opposite uniformly configured end regions, frustoconical transformer regions running inwards from the respective end regions, and a central uniformly-dimensioned region which bridges the transformer regions. The MM core is configured with a refractive step-index profile which includes a continuous dip configured to shape an intensity field of the fundamental mode from a Gaussian or dome-shaped field profile to a two-peak-shaped profile and back to the Gaussian filed profile.