Fiber Characterization with an OTDR
An OTDR trace is the "foot print" of the optical fiber. It characterizes by showing important insertion losses caused by splices, connectors, faults in association with their locations. Often it's necessary to measure using different sets of parameters to identify the type of the events correctly
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A typical OTDR
trace
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How a fiber is characterized on an OTDR trace
- OTDR works similar a radar where as the light pulses sent into the fiber get back-scattered to its receiver
- The falling straight line indicates the fiber attenuation per length (dB/km)
- A step in the continuous trace is caused either by a splice, a macro or micro bending as well as a connector
- A connectors causes additionally a huge reflection that shows up as a peak
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Two-wavelength
measurement
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Differentiation between types of fault
- Due to the complexity of the fiber structure, it often necessary to combine different measurement parameters for a proper fault identification and correct measurement values
- For instance, to differentiate between a fusion splice and a bending (disturbance), measuring with two wavelengths is necessary. While a bending causes a higher loss with longer wavelength due to the bigger mode field diameter of the light wave, a splice doesn't show much difference between the wavelengths
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The Corning OV1000 OTDR has different trace collection modes that allow the evaluation of the connected fiber at the blink of the eye. It can store data measured with different wavelengths in one file for a quick event identification... > More
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