Abstract

Externally UV-written index gratings in germanosilicate fibers have found different applications in optical communications and fiber components. The problem of control of index-grating formation requires the understanding of UV-induced processes in germanosilicate fiber core. The accepted mechanism of the photosensitivity is photoionization of germanium oxygen-deficient centers (GODC) by excitation with 5.1 eV photons. However the releasing of electron from excited-singlet-state [Fig. 1(a)] cannot explain all the experimental data, in particular the discrepancy between index change and blue luminescence change dynamics.^1,2 The possible explanation of such discrepancy is the presence of different channels of GODC photodestruction with different contributions to index change.

© 1996 Optical Society of America