Nondestructive optical fiber talk set

Communications between maintenance workers who work with nonmetallic optical cables must be conducted through optical fibers. Conventional communications were conducted by cutting the fiber at the cable joint. However, this reduces both operational efficiency and reliability. Based on the bending loss characteristics of optical fibers, we found that the light propagating in an optical fiber can be intensity modulated by U‐bending the fiber and changing the bending radius slightly. Then a nondestructive optical fiber talk‐set was developed without having to cut these fibers. In this paper, the relationship between the bending loss and modulation characteristics is investigated experimentally and the optimal bending width is determined. A talk system has been designed using terminal and intermediate talk‐sets. the required minimum modulation index and the insertion loss of the intermediate talk‐set are discussed considering the difference among fibers. the maximum line length and the allowable number of the intermediate talk‐sets are calculated based on the parameters. It is found that the allowable line length from terminal talk‐set to intermediate talk‐set and from intermediate talk‐set to intermediate talk‐set can be extended up to 80 km by adding repeater functions to the terminal talk‐sets.