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OCC-CWDM-301-18
3.2.1.1 Reflection Events
When some pulse energy is scattered, reflection events happen. When reflection event occurs, peak shows on
trace, as shown in Figure 3-1.
Figure 3-1. Reflection Event
3.2.1.2 Non-Reflection Events
Non-reflection events happen at certain points where there is some optic loss but no light scattering. When non-
reflection event occurs, a power decline shows on trace, as in Figure 3-2.
Figure 3-2. Non-reflection Event
3.2.1.3 Inspection Events
OTDR sends off a light pulse into the optic fiber to be inspected, and then receive returning light signals, and
starts calculating the “event” distance. The farther the distance is, the longer time need for scattered light to be
received by the instrument. Event distance can be calculated according to the time of receiving events signals.
Through inspection of scattered signals, properties of optic fiber, connectors and tie-ins can be identified.