| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical signal quality monitoring apparatus capable of monitoring signal quality of various optical signals. <P>SOLUTION: The optical signal quality monitoring apparatus includes a branching means which branches an optical signal to be monitored into two signals and outputs them to a first path and a second path, a coupling means which couples the optical signal from the first path and the optical signal from the second path, a measuring means which measures quality of the optical signals output by the coupling means, a delay means which is located on the first path and gives a delay to the optical signal passing therethrough, and a phase shift means which is located on the first or second path and gives a phase change to the optical signal passing therethrough. The delay means gives a delay in the coupling means so that the optical signal from the first path is delayed from the optical signal from the second path by an integral multiple of a symbol interval of the optical signal to be monitored. The phase shift means gives a phase shift to make a periodic change at least in a range from 0 to π. <P>COPYRIGHT: (C)2009,JPO&INPIT |
