| 摘要 |
<p>A branch line monitoring system and branch line monitoring method by which the SN ratio of measurement information is improved and which has a structure realized at low cost. In the system, an optical filter is provided for each optical fiber line to be monitored as a branch line. Each optical filter has cut-off characteristics such that it cuts off one of the monitoring light beams and transmits the other monitoring light beams and the signal light beam. The optical fiber lines are monitored using the monitoring light beams except the monitoring light beams cut off by the respective optical filters. Therefore, compared to the case where one optical fiber line is monitored by one monitoring light beam, the SN ratio of measurement information is improved and high-precision monitoring is possible.</p> |
