| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical transmission device, an optical transmission system and a method for testing an alarm function, capable of outputting an alarm by a remote operation during working.SOLUTION: The optical transmission device includes: an optical branch unit having at least a first port, a second port and a third port for outputting branched input light, in which a branch ratio between the first port and the second port is variable; and a control unit for controlling the branch ratio to reduce the optical level of the output light of the first port to be monitored and increase the optical level of the output light of the second port according to the reduction quantity. |
