| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable a signal light monitoring device to determine the presence of signal light with improved accuracy even in an environment subject to large optical noise. <P>SOLUTION: An optical filter 110 filters input monitor light in a transmission region where the carrier frequency of each channel to be measured is a center frequency, and then, photoelectric conversion units 130-1 to 130-n convert the monitor light filtered by the optical filter 110 into a monitor electrical signal, and a signal detection unit 150 determines the presence of signal light based on the monitor electrical signal. The S/N ratio of monitor light is increased by filtering by the optical filter 110, so that the signal detection unit 150 can determine the presence of signal light with improved accuracy even in an environment subject to large optical noise. <P>COPYRIGHT: (C)2012,JPO&INPIT |
