Fluke OF-500-01 OptiFiber, Technical Reference Handbook, Page: 130 / 278

OF-500 OptiFiber Certifying OTDR
Technical Reference Handbook
3-54
Table 3-7. Diagnosing Faults on OTDR Traces (cont.)
Small gain event (a “gainer”).
Typically caused by a splice between mismatched fibers (different backscatter coefficients, core
sizes, numerical apertures, or other parameters). Testing from the other end would show a loss at
the event’s location. The difference between the gainer’s value and the loss value is what the
event’s loss would be if the fibers were not mismatched.
Small loss event.
Bad fusion splice, a splice between mismatched fibers, a bend, or a low-reflectance connection, such as
an angled physical contact (APC) connection.
A good fusion splice between matching fiber types
typically shows only 0.1 dB to 0.3 dB of loss. If the event is a bend, it may show higher loss at a
longer wavelength. Use a visual fault locator to precisely locate bends.
-continued-