APPARATUS AND METHOD FOR MEASURING PREDETERMINED POSITION OF OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide a distance measuring apparatus capable of easily measuring the distance to the exciting point of an optical cable and a method therefor. SOLUTION: Both ends of the optical fiber 1 are connected to a terminal station 2 and a laser beam (a) is made incident on the optical fiber 1 from the terminal station 2. When the exciting point P in the working site of the optical fiber 1 is excited by use of an exciter 3, at the terminal station 2 the distance of an area on which no excitation signal is superposed is determined from the time difference between a light beam (light on route 1) which comes back through the optical fiber 1 in a counterclockwise direction and another light beam (laser beam on route 2) which comes back through the optical fiber 1 in the opposite direction, and the distance to the exciting point P is measured from the difference between the distance and the overall length of the optical fiber.