It is shown that large permanent enhancements in second-order optical nonlinearity can be induced in germanosilicate fibers (both pure and co-doped with P) by application of a transverse dc electric poling field in the presence of high intensity light. The macroscopic inversion symmetry of the core material is broken by the excitation and alignment of defect centers. Significant frequency doubling results despite the absence of phase-matching. The saturation (both with increasing dc-field and intensity) of this effect is investigated
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