Optical time domain reflectometer (OTDR)
Last Updated: Monday 30 March 2009
Optical time domain reflectometer (OTDR) is an instrument used to characterise an optical fibre.
An OTDR injects a series of optical pulses into the fiber under test. It also extracts, from the same end of the fiber, light that is scattered back and reflected back from points in the fibre where the index of refraction changes. The intensity of the return pulses is measured and integrated as a function of time, and is plotted as a function of the optical fibre length.
The OTDR may be used for estimating the fiber''s length and overall attenuation, including spliced and mated-connector losses. The OTDR is also used to locate faults, such as breaks
