FBP PRoBE & HP3-60-P4 InsPEct and tEst systEm
23
FiBer insPection & testinG
6
Fiber Inspection & testing
cHaPter 6
Dirt is everywhere,
and a typical dust particle (2–15 μm in diameter) can significantly
affect signal performance and cause permanent damage to the fiber end face. Most field
test failures can be attributed to dirty connectors, and most of them are not inspected
until the problem is detected,
after
permanent damage has already occurred.
When dirt particles get on the core surface, light becomes blocked, creating unacceptable
insertion loss
and
back-reflection
. Furthermore, these contamination particles can
permanently damage the glass interface by digging into the glass and leaving pits when
mated, causing further signal loss. Damage also occurs when large particles of dirt on the
cladding layer and/or the ferrule cause barriers that prevent physical contact, creating air
gaps in the connection. These large particles are also known to break apart and migrate
across the fiber surface when mated.
OTDR Trace of
Contamination and
its Effect on Signal
Performance
Introduction
