| 摘要 |
<p>At both end parts of a specified section of a high tension line and close to it, a first Faraday device (33a) and a second Faraday device (33b) are disposed, and output end of the first Faraday device (33a) is connected to the input end of the second Faraday device (33b) through a polarization plane retaining type optical fiber (39). A light having a linear-polarized polarization plane is inputted from a polarizer (32) to the input end of the first Faraday device (33a). The light output from the second Faraday device (33b) is led through an analyzer (34) to a photoelectric device (15), whose output is processed by an electric circuit consisting of only one band-pass filter (21), only one DC filter (22), only one divider (23), and a judgment circuit (25). <IMAGE></p> |
