| 摘要 |
<p>PURPOSE:To make the cable free of metals to make the cable light-weight and narrow-diameter, by using a photodetector of gaseous pressure and by transmitting the pressure signal of this detector through the fiber in the cable as a light signal. CONSTITUTION:Light 16 from light source 11 is incident to interposed fiber 15 through directional coupler 13 and is incident to photodetector 14 of gaseous pressure in connection part 4. This light becomes light output signal 17 corresponding to change of gaseous pressure and is returned to interposed fiber 15 again and is input to the light receiver through directional coupler 13. By this constitution, if a fault occurs in the cable, the light output of the photodetector of gaseous pressure near the faulty point changes to change the light receiving level of light receiver 12 corresponding to the connection part, and therefore, the fault is found and the faulty position is searched rapidly and easily.</p> |
