OTDR OPERATION BASICS

OTDR OPERATIONS

OTDR: What it is

OPTICAL TIME DOMAIN

REFLECTOMETER,

OTDR Working Principle

The OTDR’s operating principle is based on the measurement of the Raleigh Backscattering Signal, generated by

sending a high power optical pulse from the OTDR through the optical fiber. Light

is reflected back to the OTDR.

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This backscattered light is measured by the sensitive optic receiver, converted to digital form and averaged to improve the signal to noise

ratio

The resulting signal forms a graph called a TRACE. The trace is a visual representation of the backscattering coefficient created by the OTDR to determine the “events.” The trace

shows the “events” on the fiber optic link such as breaks, splice loss, bends,

attenuation and distance

OTDR MACHINE WINDOW MENU

5 Basic menu every OTDR must have•Trace title•Menu bar•Button toolbar•Information Panel•Trace window

,

TRACE TITLE

TRACE WINDOW

BUTTON TOOLBARMENU BAR 

INFORMATION PANEL

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GENERAL OTDR FEATURES

OTDRS CAN BE CATEGORIZED BY

•Their operating wavelength, •Their dynamic range (the length of optical fiber link over which they will operate),•Their sensitivity or resolution. OTDR sensitivity is its ability to differentiate between closely spaced events.

OTDR OPERATIONAL TOOL BAR

THESE ARE THE TOOLS FOUND ON THE BUTTON TOOL BARS FOR THE

SMOOTH OPERATION AND ANALYSIS OF THE OTDR TRACE

Attenuation measurement by straight-line trace approximation [D]

Restores all trace scales [ALT+BKSP]

Opens up the measurement parameters window

 Starts the measurement process in real time

mode [ENTER]

Vertical zoom out control [CTRL+V]

Automatic trace analysis [A]

Deletes all the marks between markers [ALT+DEL]

Horizontal zoom out control [CTRL+H]

Applies a template to current trace [CTRL+T

Inserts trace from clipboard onto host trace [SHIFT+INS]

Trace information [I]

Reflection coefficient measurement [R]

OF refractive index adjustment [N]

Inserts a mark for the current mode and marker position [CTRL+ENTER

Opens a table of the current trace marks [Т]

Copies current trace to clipboard [CTRL+INS]

Deletes inserted trace [CTRL+DEL]

Horizontal zoom in control [H]

Vertical zoom in control [V]

Attenuation measurement in OF junctions [S]

Attenuation measurement between two points mode [P]

Starts the measurement process in Normal mode

Saves a current trace [CTRL + S]

Prints a current trace

Opens a previously saved trace [CTRL + O]

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 OTDR Operations

In addition to the trace analysis, the OTDR will determine the following Distance of the fiber linkAttenuation of the fiber linkThe fibers ORLSplice lossConnector loss

WHAT TO OPERATE ON OTDR

Every OTDR user must know how toadjust the distance to be displayed on the screenadjust the dB for vertical scale representationsselect various wavelengthsadjust the transmission pulse widthsselect a vertical position on the screen using the curserprint, save, and execute other file commands

OTDR ACCEPTANCE TEST

Acceptance testing provides a quality assurance notification to the installation crew that the cable meets the manufacturing standards, and is not damaged. It ensures that:•the cable meets the manufacturer's specifications for optical attenuation requirements•the footage of the reel is correct•the cable remains undamaged from shipment and handling

THERE IS MORE TO

OTDRin the aspect of its

TECHNOLOGY, FUNCTIONALITIES AND

MAINTENANCE

THANK YOUfrom

Intra-Metropolitan Technologies (IMT)

www.imtcomputers.net

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