Triple-Play Service Deployment

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These effects result in an easy-to-understand signature of the link
as long as there is only one branch along the link. Because a PON
network provides multiple branches along the link, the PON OTDR
signature becomes very complex to interpret. This is because the
OTDR is not able to differentiate the reflected light coming from a
default of one branch location to another branch location, since
they are located at the same distance to the OTDR. The result is an
aggregate trace that does not display the effect of each branch
individually. Rather, it displays the effect of all of the branches at
the same time.
PON Reflectometer Trace Analysis takes into consideration the
backscatter response after the splitter that is used in PON
networks. It allows for the identification of the optical branch, the
localization of faults, and attenuation estimation.
Therefore, in order to analyze a PON network, a specific test
procedure, described in Appendix A, is required.
JDSU T-BERD®/MTS 6000 Compact Optical Test Platform with OTDR
Chapter 3: Deploying and Troubleshooting Fiber Networks