PHOTOCHROMIC DOPED SOL-GEL MATERIALS FOR FIBEROPTIC DEVICES

Photochromic-doped sol-gel materials have been prepared by adding a sp iropyran photochromic dye to a solution of ethoxy silane monomers cont aining non-reacting ethyl radicals. After polymerization, normal photo chromism (i.e., colored material upon UV irradiation) is obtained in t he resulting matrix. The sol-gel matrix hinders the organic molecule r otations, thus giving two stable states, which can be reversibly switc hed by UV and green-blue irradiation respectively. If these materials are attached to optical fibers, the properties of the light throughput may be modified. Simple fiber-optic/photochromic devices made of two optical fibers placed in a V-groove removable connector have been prep ared. Once cured, these devices behave as optically addressed variable delay generators. The same devices can be used for preparing simple o ptical switches and routing systems.