Study on the photosensitivity of photosensitive fibers

The photosensitivity of photosensitive fibers is studied experimentally and theoretically. In the experiment, the relationship between the diffractive index increment of photosensitive fibers and UV irradiating dose based on an unbalanced Mach-Zehnder Interferometer (MZI) is measured. The experimental results show that the photo-induced index's increment of photosensitive fibers is multi-decaying-exponentially proportional to the UV irradiating dose and the order of magnitude of the maximum value can reach 10 -3 . In order to explain the relationship, a new assumption is proposed, which can give a good explanation based on the "color center model" and the "Kramers-Kronig" principal.