| 摘要 |
<p>O In a known optical cable, optical fibers (24) are loosely laid in a number of grooves (16) formed within an elongate plastics extrusions (14). Typically the grooves (16) follow a helical path with periodically reversing pitch, the helices centered on a central longitudinal axis of the cable. A primary reason for the helical lay is to prevent the fibers (24) from becoming stressed should a bend occur in the cable. A further benefit of loose laying of fibers (24) in a helical groove (16) of periodically reversing pitch is that any elongation of the cable core is not immediately transmitted to the fiber (24) supported by it. The fiber (24) will move from its initial loose laid position both in a direction towards the inside curve (20) of the helix and in a direction towards the base (22) of the grooves (16). When it bears against the cable core over an appreciable length, the fiber (24) will then be subjected to tensile stress. By the invention, tolerance to core elongation is increased by arranging that the grooves (16) at any point along the core cant towards the outside curve (25) of the helix.</p> |
