Abstract

Since the discovery of the phase grating formation in optical fibers by Hill et al., there have been considerable efforts both experimentally and theoretically to understand the governing physical mechanism. The microscopic description of the formation of the photosensitive grating is still unclear. Recently, however, it was shown that a local two-photon bleaching model could explain both the experimentally observed time dependence of the reflectivity and the role of Fresnel reflection at each end of fiber.¹ Parent et al. were the first to observe that the refractive index changes induced in optical fibers by grating formation were anisotropic.² In this paper we generalize the local two-photon bleaching model to describe the anisotropic grating formation in birefringent optical fibers and, using symmetry arguments, we show that there are only two important material parameters. We show that the dynamics of the polarization grating formation exhibits a universality similar to that seen in the dynamics of Bragg gratings, and study how the dynamics of the grating development is related to the material parameters.

© 1991 Optical Society of America