Test Parameters

Select the type of test to perform from the Mode drop-down menu: Manual, Auto, Manual Real Time, Auto Real Time, V-Scout or MPO Auto(with OX-MPO-12 optical switch connected).

 

Expert OTDR (Manual) Mode

To set OTDR test parameters manually, under Test Parameters select Manual from the Mode drop-down menu.

 

OTDR Setup: Manual Mode

 

EZ-OTDR (Auto) Mode

To set OTDR test parameters automatically, select EZ-OTDR from the Fiber Main Menu or on the Test Setup screen, select Auto from the Mode drop-down box. In this mode, the OTDR performs a measurement and analysis of the fiber and determines optimal test settings automatically.

Auto mode is intended for inexperienced operators and uses single pulse per wavelength. The type of network to be tested must be specified.

 

OTDR Setup: Auto Mode

• Network: type of network in which fiber is being tested:
  (Use the 'Pencil' icon to select the Network configuration.)
  
  • P2P - Point-to-Point. Use to test non-PON fiber lines.
  • PON/B (2 SPL) - PON Balanced. Use to test ONT to OLT.
    • Select up to three balanced splitters.
  • PON/U - PON Unbalanced (Advanced PON Test Mode). Use to test ONT to OLT.
    • Tests up to eight unbalanced splitters and/or taps.
    • A manual link definition is recommended.
  • PON/T - PON Taps. Use to test ONT to OLT.
    • Tests up to 20 taps.
    • A manual link definition is required.
  • Splitter to ONT - Use to test Splitter to ONT. This is similar to P2P, but measures Reflectance at End. If Refl is -30dB to -40dB, the ONT icon appears on the LinkMap. If there is no Reflectance or Reflection is outside of the range, then the LinkMap will show the End icon and add a message that NO ONT was detected.
  • ONT to Splitter - Use to test ONT to Splitter. This is similar to P2P, but the analysis stops at the Splitter. The Splitter icon will appear on the LinkMap if scatter after the 1st splitter is detected; otherwise, the LinkMap will show the End icon and add a message that no splitter was detected, which could indicate a cut or bend in the drop fiber. If needed, use the second larger pulse width so scatter after the splitter is detected, but only displays the short pulse width trace.
• Distance range (km, m, miles, kilofeet, ft) [manual mode]: maximum value of measured distances; the value of distance range should exceed the expected length of the fiber under test (20% more). The distance unit type can be set by clicking the View Setup button.
• Pulse Width, ns [manual mode]: the value of the optical pulse duration; the range of available optical pulse values depend on the selected distance range and is set by the OTDR software automatically (10 ns pulse ~ 1 meter). Short pulse widths provide better resolution and produce the best event and attenuation dead zones. Short pulse widths, however, inject less optical energy into the Fiber-Under-Test (FUT), resulting in a noisier trace and lower dynamic range. Longer pulse widths provide the highest dynamic range and are used to test long fibers.
• Resolution, m [manual mode]: distance between two data points (sampling interval) of the trace; values depend on the selected distance range. Select smallest value to measure events spaced close together and use largest value to for longer ranges. Auto mode will determine best value for Fiber Under Test.
• Time, min:sec [manual mode]: determines the duration of measurement process with averaging. Use Live mode to perform monitoring of the fiber in Real Time. Longer averaging time improves the SNR and produces a "smoother" trace.
• Optimized For [manual mode]: test modes - Automatic DR/DZ, DR (maximize dynamic range), or DZ (best dead zone, sacrifice range).

 

Other Parameters

• Fiber Model: Select the type of fiber to be tested to auto populate Index of Refraction (IoR) and Backscatter co-efficient (BS) values. To modify values, click the pencil icon  to the left of the Fiber Model field to access the Fiber Models screen. Then, tap Modify to Add, Rename, or Remove values.

An incorrect Index of Refraction can affect measured length results. Incorrect IoR and Backscatter values can affect Reflectance and ORL results.

OTDR Setup: Fiber Models

These settings apply to the next measurement only. To edit RI and BC for a previously measured fiber trace, use the Information button on the Traces tab. Refer to Measurements for details.

• RI (Refractive index, N): Setting for each available wavelength (also known as group index) is used to convert time to distance. Setting proper value (1.2000-1.8000) determines accurate distance measurement.
  Refractive index can be changed for any stored trace. Enter a custom value or select fiber type to populate corresponding values by selecting file(s) using the Traces tab.

• BC (Backscattering coefficient, BC): Represents level of backscattering in a particular fiber. It is used for Reflectance and ORL measurement and can be obtained from the fiber manufacturer. Backscattering coefficient can be changed for any stored trace.

  Use the Refractive Index (IoR) and Backscatter coefficient as provided by the cable or fiber manufacturer.

• Thresholds - Refer to Thresholds for details.
• Front Panel Check: Tests OTDR connection and displays warning indicating when the launch level is 1.5 dB lower than expected or if initial reflectance is too high (-35dB is default fail threshold). If needed, stop and clean connectors, or proceed with the bad connection.

For OTDR with built-in internal launch fiber, (G.657), the OTDR connector insertion loss will depend on the fiber type connected to the test set. Mismatched fibers can result in higher connection loss than expected connector loss. Use the Span button to enter fiber mismatch compensation or de-select Include Event Loss. Mismatch fibers should not impact Reflectance if the correct Fiber type is selected.

Reports Insertion Loss and Reflectance, and also advises if acceptable or not. When testing PON or xWDM MUX, use a launch fiber between the test set and Splitter or MUX or disable this feature.

When connected to a fiber with traffic (live), a warning is displayed. As long as the signal exceeds the threshold, the test will continue. IF the signal is removed, press OK to resume testing. Pressing Abort will permanently disable the test, requiring the need to close OTDR application and reboot the test set.

 

• Span Begin (Launch): Enter Length or Index. Used to identify where a launch cable ends and test fiber begins. Defines the start of the Fiber Under Test. This appears as a green bracket with arrows pointing right on screen.

  If Event #1 is the end of the launch fiber, set the Span Begin Index to "1".

• Span End (Receive): Enter Reverse Length or Reverse Index. Defines the end of the Fiber Under Test. This will appear as a large green arrow pointing left on screen. If a launch fiber is used at the far end of the test fiber, set the Span End Index to the Event # associated to the location where the far end launch fiber starts.
• Include Event Loss: Check to not include connector loss in Total Loss Summary.

  If Event Loss is not checked, the LinkMap will state that the event loss is not included.

• Compensated Loss (dB): For OTDR with built-in internal launch fiber, (G.657), the OTDR connector insertion loss will depend on the fiber type connected to the test set. Mismatched fibers can result in higher panel loss than expected connector loss. Use the Span button to enter fiber mismatch compensation. Mismatch fibers should not impact Reflectance.

The same procedure for offsetting Launch Fibers applies to offsetting Receiver fibers which are often used in Fiber to The Antenna (FTTA) applications.

Measure Cables

Use the Measure button in the Span settings to measure the Launch/Receive cables and populate the result into the Length field automatically.

 

 

To measure cable length:

1. Click the Measure button. The Launch and Receive Fiber Measurement screen is displayed.
2. Select which cable (Launch only, Receive only, or Launch and Receive) to measure. To measure both cables (Launch and Receive), connect the cables together, but this requires a connection to have -55dB reflectance. Then, click OK. The Launch and Receive Cable Measurement screen is displayed.

   

   OTDR Setup: Auto Measure Cables

3. Tap Measure to begin. After the measurement is completed, the measured lengths will populate the fields automatically. To reject the values, click Cancel. To accept the values, click OK. The new measured length(s) populate the Launch and Receive Cable Calibration (Span settings) screen.

   If the Launch and Receive option is selected and the cables are not connected, you will receive a "Can't find the R>=-55dB coupling event; try measuring each cable individually".

 

AutoSave Button

Use the Autosave option to configure options for saving results automatically with default information in the filename. Refer to Autosave Parameters for details.

 

Cloud Button

Use the Cloud option to store test results and files to the cloud. Refer to Fiberizer Cloud for details.

After setting up the Cloud Parameters, test results can be pushed to the account on the Cloud. Refer to Results Tab.