Abstract

Second-order nonlinearities can be induced in germanosilicate (GS) glass fibers in a variety of ways: by coherent superposition of pump and second-harmonic light (a third-order dc polarization P_dc³ is induced that breaks the inversion symmetry¹); by excitation poling with blue light and an external dc field,² E_pol; and by strong E_pol’s in the absence of light.³ There is as yet no satisfactory agreement over the nature of the underlying alignment process. From related detailed studies of color-center behavior in GS fiber,⁴ we have formulated a self-consistent model as developed in the following points.

© 1990 Optical Society of America