High-temperature stability of optical transmission properties attained by liquid-crystal polymer jacket

Liquid crystal polyester (LCP) tight jackets, developed as secondary coatings on optical fibers, exhibit Young´s moduli of 10-20 GPa and linear expansion coefficients on the order of 10^-6/°C. Because of their low linear expansion coefficients, and because they exhibit no thermal shrinkage, the LCP jackets cause a slight change in fiber strain on the order of 10^-4percent/°C, or a change in the thermal coefficients of the transit time delay as low as 14-29 ps/km°C in an 80 to -60°C temperature range for tight-jacketed optical fibers. Furthermore, the LCP tight-jacketed optical fibers exhibit no excess loss in this temperature range.