| 摘要 |
<p>PURPOSE:To minimize the elongation of an optical fiber by stringing the compound cable with tensile strength larger than the normal one applied beforehand and by making the elongation of the optical fiber equal to the contracted quantity of a cable section when it is returned to the normal tensile strength. CONSTITUTION:With a traction means, tensile strength is applied to the compound cable. If this tensile strength is increased up to the normal tensile strength 1, the elongation of a cable section (a) will be beta and that of an optical fiber (b) will be . Under this condition, when the traction is stopped and the other end of the cable is fixed to a steel tower, the elongation will remain to the optical fiber. Furthermore, if the tractive force is increased and the compound cable is elongated up to the condition of tensile strength 2, elongation gammais given to the cable section while an elongation is given to the optical fiber. If the tensile strength is lowered to the normal one 1 once again, the cable section will by contracted (gamma-beta). If then the tensile strength 2 is determined so as to be equal to the elongation quantity alpha of the optical fiber, the elongation, alpha of the optical fiber can approximately be reduced to zero when the tensile strength is returned to the normal one 1.</p> |
