Abstract

Since the first discovery of the photosensitive phenomena in optical fibers by Hill et al.,¹ 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. However, the experimental data appear consistent with the assumption that two-photon absorption leads to a modification in the growth of the grating. In this paper we study the dynamics of grating formation, taking into account the effects of boundary conditions at both ends of the fiber. The analysis is based on the coupled-mode equations for the interaction of two, oppositely propagating waves inside the fiber and the assumption that the dielectric constant changes owing to two-photon absorption. We solve the coupled, nonlinear partial differential equations analytically for various special cases of boundary conditions and discuss both the overall growth of the grating and oscillations in the reflectivity that appear as it develops. Our results are compared with numerical simulations.

© 1990 Optical Society of America