IDEAL INDUSTRIES FIBERTEK, Руководство пользователя

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CHAPTER 6
FIBER OPTICS DIAGNOSTICS
(TRACETEK
TM
)
TRACETEK is a Reflective Anomaly Detection (RAD) system composed of two parts:
¾
LANTEK Cable Certifiers, and
¾
TRACETEK Optical Transceiver Module
The LANTEK Display Handset provides power, user interface, storage and signal
processing capability to the TRACETEK module. The TRACETEK module converts the
LANTEK electronic TDR signals to optical and optical signals back to electronic.
The primary use of this system is to locate optical reflections from cable discontinuities
such as connectors, splices, fractures (i.e. cracked or broken strands) or other
anomalies occurring within an optical fiber network.
Warning: The TRACETEK adapter generates light pulses exceeding 40 milliwatts
of power. DO NOT look into the adapter or the fiber under test as serious eye damage
may result.
TRACETEK is an alternative to using an OTDR (Optical Time Domain Reflectometer)
and functions in a similar manner. Both methods will produce traces of optical back
reflection for analysis by technicians. However, the Rayliegh scatter measurement
used by the OTDR to infer fiber loss is not used in TRACETEK.
Note: True loss measurements can only be made with an Optical Loss Test Set such
as TRACETEK’s companion product, FIBERTEK.
TRACETEK VS. OTDR
OTDR OPERATING PRINCIPLES
The OTDR (Optical Time Domain Reflectometer) is a device that is able to “look” at a
fiber optic cable and display a graphical representation of the events that occur on the
cable. The basic concept is that a high-speed laser fires a precise pulse of light into
the fiber, after which the device monitors the same fiber for reflections. The time
between the launched pulse and reflected pulses represents the distance to the events
that caused the pulses. This gives the OTDR the ability to not only measure the length
of the fiber but to also measure the distance to each event on the fiber. This function
allows the OTDR to be used as a trouble-shooting tool to find breaks in the fiber and
to identify the location of individual connectors and splices.
The second feature of an OTDR is its ability to measure the tiny amounts of light that
are reflected back by the fiber optic cable itself. This phenomena is known as Rayleigh
scattering and is caused by light reflecting off molecules in the glass whose diameter
is 1/10 the wavelength of the light. This is the same phenomenon that makes the sky
appear blue. When the OTDR is able to detect these tiny reflections it can calculate the
loss of the cable as well as the insertion loss of connectors and splices on the fiber
cable.
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