Optical fiber locator

Abstract

Abstract PURPOSE:To confirm a fracture point regardless of the length of an optical fiber by increasing automatically the period of light pulses sent out to the optical fiber and detecting a shift in the peak position of Fresnel reflected light from the fracture point. CONSTITUTION:Output pulses of a clock part 1 are passed through a period selector 2 and light pulses from a laser diode 3 are sent out to the optical fiber 5 rhrough a coupler 4. Reflected light from an optical fiber cable 5 is converted photoelectrically by an avalanche photodiode 6. The mean value of measured values is calculated by an adder 9 and processed by a processing part 10 to be displayed on a display part 11. The length of the optical fiber is more than the limit length of the pulse period, so the reflected pulse appears in the area of the next period and the fracture point is easily recognized by mistake. When the period is increased several times, the reflection peak of the fracture piont appears at different places. When the length of the optical fiber is less than the limit length determined by the pulse period, the position of reflection is unchanged even when the period is increased. Thus, the period is increased automatically to measure the fracture point accurately without erroneous recognition.

Inventors

• 👤 Yoshinori Ishihata
• 👤 石幡　吉則
• 👤 Kazuyoshi Shikayama
• 👤 鹿山　和義
• 👤 Fujio Otsuka
• 👤 富士夫 大塚
• 👤 Mikio Hotta
• 👤 堀田　幹生
• 👤 Hideki Noda
• 👤 秀樹 野田
• 👤 Yosuke Furuta
• 👤 古田　洋介

Bibliographic Details