Triple-Play Service Deployment

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Recommended test tools
Whether the user is deploying a point-to-point network or a PON,
the final acceptance test is ultimately the process of characterizing
the complete optical network. It includes continuity checks,
insertion loss and optical return loss measurements of the
end-to-end network through analysis of the transmission optical
wavelengths. A minimum of two wavelengths are selected (usually
1310/1550 nm) in order to identify any macrobends along the
network, a common fault when installing short distance and high
fiber count networks. The loss generated by a bend increases as
the test wavelength increases. For example, if a localized section
has a loss of 0.2 dB at 1310 nm and a loss of 0.5 dB at 1550 nm, then
this can be clearly identified as a bend. Other point losses do not
vary significantly with wavelength.
Figure 3.17 Screen capture of OTDR trace with bending
Chapter 3: Deploying and Troubleshooting Fiber Networks