A high-strength, low-linear expansion coefficient tight-jacketed optical fiber is proposed using thermotropic liquid crystal polymer (LCP). The 0.9-mm-diameter LCP-jacketed optical fiber with breaking strength of 51 kg at strain of 3.4% at 25 can be used over the wide 60 to 200 temperature range.

Primary silicone-rubber/secondary liquid-crystal-polyester (LCP)-coated optical fibers have loss increases as low as 18 dB/km even at liquid uitrogen temperatures. This result can be explained by both low contraction and the buffer effect against heat shock of the secondary LCP layer which results in less fiber bending.

The loss change for liquid-crystal-polymer(LCP)-jacketed optical fibers has been investigated under lateral load. A 0.7 mm LCP-jacketed optical fiber has the same lateral-load resistance as that of a conventional 0.9 mm nylon-jacketed fiber to continuing constant lateral load.