A materials approach toward the mitigation of nonlinearities in glass optical fibers

Power scaling in high energy fiber-based laser systems is limited by optical nonlinearities. As opposed to the complex micro-structured large mode area (LMA) fibers typically developed to mitigate these parasitic nonlinear effects, the present work instead advocates another approach, a material approach, in which nonlinearities are mitigated through a judicious choice of dopants in the fiber core. To demonstrate the effectiveness of this approach, multicomponent core - silica glass cladding optical fibers are fabricated using the molten core method and the role played by the glass dopants in the mitigation of nonlinearities discussed. More specifically, highlights are made on multicomponent alkaline-earth (Sr, Ca) doped-silica fibers exhibiting concomitant reduction of > 6 dB in the Brillouin gain coefficient, 1 - 2 dB in the Raman gain coefficient, and 2 - 3 dB in the thermo-optic coefficient relative to conventional silica fibers.