| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that when a high power optical signal by a malicious user and a false signal for unauthorized access, or an optical signal of wavelength not allocated from an OLT are input to an ONU side optical fiber in a WDM-PON system, the communication quality of other users may be affected and moreover the receiver of station side may be damaged. <P>SOLUTION: By equipping an optical shutter in a position near an optical splitter of the ONU side of an optical branching portion, when the input of an extraordinary light is detected, the light path in which the extraordinary light is input is shut off, thereby the input of extraordinary light to an optical line which the OLT and a plurality of users share is prevented beforehand. <P>COPYRIGHT: (C)2010,JPO&INPIT |
