Fiber DFB lasers with ultimate efficiency

A novel method for designing distributed feedback (DFB) lasers with ultimate efficiency is presented. The method is based on the calculation of the optimum signal distribution for a given pumping scheme and derivation of the grating profile that sustains this distribution so that at every point in the cavity pump-to-signal conversion efficiency is maximum. Theory applied experimentally in Er-Yb co-doped fiber resulting in a 57% increase in the efficiency with 10% shorter device length compared with standard optimized co-pumped designs.