OTDR Testing is carried out with Tri Band test equipment and based on your own requirements can be either Uni or Bi-directional. The Tri Band testing covers the O, C and L Bands.
The Optical Time Domain Reflectometer (OTDR) is a powerful fiber optic test instrument in that it acts like an optical radar in locating sources of error with the fiber system.
It yields a plot, or trace, indicating the loss versus distance.
This information allows events in the optical fiber system such as fiber splices and connections to be located and their loss measured.
The OTDR is a complex instrument and so detailed interpretation of an OTDR trace is a job for an experienced or expert fiber tester.
The OTDR is not the reference test method for fiber attenuation, this being an ILM technique, and indeed the OTDR has some short-comings as an accurate loss measurement instrument.
Where the OTDR does dominate is in the spatial information it provides on any fibers with high attenuation or any poor quality splicing.
The other advantage of this technique is that the stored trace shows exactly how the measurement was conducted, something the ILM technique does not provide, and this allows an expert OTDR trace analyser to know something of the quality of the measurement results provided.