USER'S MANUAL. PROLITE-50/51/52
4. BASIC INFORMATION OF PROLITE-50/51/52
4.1 Principle of Prolite-50/51/52
OTDR is a measurement instrument for identifying optic fiber transmission
features. The instrument is mainly used to measure attenuation of a whole optic fiber
chain and provide attenuation details relating to length, namely detect, locate and
measure any event in optic fiber chain (events refer to faults caused by welding,
connectors, and bending whose transmission change can be measured). Its non-
destructive,
one-end
PROLITE-50/51/52 an indispensable tool for manufacture, construction, and
maintenance of optic fiber.
The faults and heterogeneity of optic fiber it self cause Rayleigh scattering of light
pulse transmitted in optic fiber. Part of light pulse is scattered in the reverse direction,
and this is called Rayleigh backward scattering, which actually provides attenuation
details relating to length.
Information relating to distance is obtained through time information (that's the
reason why there is "time Domain" in the name of OTDR). Fresnel reflection occurs at
the boundary between two media of different IOR (for example, connections of faults,
connectors, or optic fiber end). This reflection is used to locate the discontinuous points
on optic fiber. The magnitude of reflection depends on the difference between IOR and
the smoothness of boundary.
PROLITE-50/51/52 sends out a light pulse into connected optic fiber, and receive
reflections of events and backward scattering power of pulse in time. Locus will be
displayed on LCD. The y-axis is dB value of backward scattering power, and the x-axis
is the distance.
4.2 Basic definition and classification of events
4.2.1 Events
Events refer to any abnormal points causing attenuation or sudden change of
scattering power besides the normal scattering of optic fiber, which include all kinds of
losses like bending, connections and ruptures. Events points displayed on LCD are
abnormal points that cause traces to deviate from straight line.
Events can be classified as reflection events and non-reflection events.
11-2015
connection,
and
rapid
measurement
has
made
the
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