Intrinsic and Extrinsic Properties of Fiber Optic Sensor Materials.

The major sources of extrinsic absorption and scattering losses in fluorozirconate glasses and fibers have been identified. The origin of transition element impurities has been determined and a new separation process for their removal has been developed. A new reactive atmosphere process for reducing anion impurities is currently in use. Hydroxide contamination from atmospheric water has been recognized and glass processing and rod casting is being conducted in a specially designed atmosphere controlled glovebox. A recent modification will allow for the rotational casting of preforms within the glove box. Two processes suitable for preparing multimode preforms have been developed. Their applicability for single mode preforms, essential for long length repeaterless data transmission, appears promising. The extent of drawing induced scattering loss has been determined and its reduction can be expected with the use of atmosphere controlled RF furnace. Continued reduction in total extrinsic loss can be expected as these techniques and processes are totally integrated into the low loss fiber program.