摘要 |
In the case where, in a WDM-PON system, a high-output optical signal or a pseudo signal for illegal access by a hostile user, or an optical signal with a wavelength which is not assigned from an OLT is input to an ONU-side optical fiber, the quality of communications for other users is possibly affected and a receiver on the station side is possibly destroyed. By providing an optical blocking unit at a position near an ONU-side optical splitter of an optical branching unit, in the case where input of an extraordinary optical signal is detected, an optical route into which the extraordinary optical signal is input is blocked, so that the input of the extraordinary optical signal to an OLT and optical lines shared by plural users can be preliminarily blocked.
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