OTDR stands for optical time domain reflectometer, and is an optoelectronic instrument that is used to characterize specific optical fibers. This tool injects optical pulses in series into fibers for testing as well as extracting light form that fiber that is reflected back from points in that specific fiber where the refraction changes. The strength of return pulses are then measured in time and then plotted under a function of the fiber length.
OTDR tools are used for helping to estimate the length of fiber’s attenuation such as splice and connector losses. This tool can also be used to help find faults or breaks and to measure the optical return loss. These tools are also used for their graphical display, as they can offer additional test automation, and requires special training and experience to use properly even though the information provided on screen is self explanatory.
OTDR tools are used to find the loss or length of a fiber from the point of manufacture to cabling and warehousing in a drum, then through installing and splicing. OTDR manufacturer tests are stored for later use of fiber failures or warranty problems, as these failures can be very expensive. These tools are commonly used for finding faults in systems that are already installed. Reference in these cases helps to find where the problem lies. Using an OTDR for finding faults requires a professional operator who can determine the settings required for such a job, especially in cases over longer distances or splices and connectors that are closely situated with other PONs.