Abstract

Many applications, both civilian and military, proposed for optical fibers, involve use in severe mechanical environments. Because of their load- time-length requirements, short time proof testing at up to 300 ksi (2.1 GPa) in 10-30-km lengths may be necessary to assure satisfactory in-service performance. Although great strides were initially made in understanding the practical factors influencing the strength of long lengths of glass fiber, the control of these factors in a production environment has proved to be difficult. A gradual improvement in the strength of moderate amounts of fiber (25-50 km) has been noted in the recent literature. The probability of a 5-km long fiber passing 100-ksi (0.7-GPa) proof testing has increased from less than 0.1% in 1975¹ to values of 10-90%^2-4 depending on raw material quality, heat source, and cleanliness and care taken in processing.

© 1981 Optical Society of America