Inverse Scattering Designs of Active Multimode Waveguides With Tailored Modal Gain

Abstract

Darboux inverse scattering transforms are used to design active waveguides with individually tailored modal gain, introducing areas of distributed gain and loss inside the waveguide. Potential applications of such devices include multimode optical amplifiers for which mode-dependent loss and its associated deleterious effects on channel capacity have been compensated. We also show that the commonly used ring-doping approach to modal gain equalization in fibers is a subset of the design approach utilizing gain and loss that derives from the inverse scattering theory.