How to adjust an FTB200 optical time domain reflectometer

Adjusting an FTB200 OTDR involves connecting the fiber correctly, setting the wavelength, pulse width, and measurement range, and selecting the appropriate trace acquisition mode for accurate fiber characterization.

Connecting the Fiber

Begin by securely connecting the fiber under test to the OTDR using the correct launch fiber to minimize dead zone effects. Ensure all connectors are clean and properly seated. Never insert or remove modules while the FTB-200 is powered on, as this can damage the device . If your OTDR has a Visual Fault Locator (VFL), use it cautiously to avoid direct eye exposure to the laser .

Setting OTDR Parameters

Adjust the following key parameters for optimal measurement:

• Wavelength: Choose the appropriate wavelength for your fiber type (e.g., 1310 nm or 1550 nm for singlemode, 850 nm or 1300 nm for multimode) to detect specific events and losses .
• Pulse Width: Select a pulse width that balances resolution and dynamic range. Shorter pulses provide finer resolution for closely spaced events, while longer pulses allow longer distance measurements .
• Measurement Range: Set the range to cover the entire fiber length. Auto mode can calculate this automatically, but manual adjustment may be needed for complex networks .

Trace Acquisition Modes

The FTB200 offers multiple acquisition modes:

• Auto Mode: Automatically calculates fiber length, sets acquisition parameters, and acquires traces. Ideal for quick tests or standard fiber spans .
• Advanced Mode: Provides full control over all test parameters, allowing detailed analysis of splices, connectors, and total fiber loss .

Performing Measurements

Once parameters are set, initiate the test. The OTDR will generate a trace showing backscatter and reflections along the fiber. Analyze the trace to identify:

• Fiber breaks or faults
• Splice and connector losses
• Total fiber attenuation and length For improved accuracy, consider bidirectional analysis, which averages measurements from both ends of the fiber to reduce errors in loss calculations .

Safety Considerations

Always follow laser safety guidelines. The FTB200 is a Class 3R laser device, so avoid direct eye exposure to the laser beam. Ensure the laser safety LED is off before handling fibers .

Summary

To adjust an FTB200 OTDR effectively:

1. Connect the fiber using a launch cable and clean connectors.
2. Set wavelength, pulse width, and measurement range according to fiber type and test requirements.
3. Choose the appropriate trace acquisition mode (Auto or Advanced).
4. Perform measurements and analyze traces for faults, losses, and fiber length.
5. Use bidirectional analysis for more accurate loss measurements.
6. Follow all safety precautions to prevent laser exposure. These steps ensure precise fiber characterization and reliable OTDR testing results .