Ionization-induced nonequivalent absorption in a birefringent silica fiber

The response of a single-mode highly birefringent fiber, operating at a wavelength of 1.3 mu m and irradiated by a source of 200 MeV pulsed protons, is presented. The fiber fast and slow axes of birefringence were optically excited and observed to exhibit transient absorption at different rates which scaled linearly over the pulsed exposure range of 2.6-17.4 krad (Si). Mechanisms possibly affecting the fiber birefringence are discussed including the introduction of transient electric and magnetic fields arising from the ionizing radiation.>