Attenuation refers to the amount of signal loss as it travels down the fiber, typically expressed in dB/km. Losses can be caused by scattering, absorption, dispersion & bending. Optical Time Domain Reflectometers (OTDR) are widely used with telecommunications products and systems for testing bare and cabled fiber, as well as performing final system acceptance testing. This type of testing is the most accurate testing available and is the most accurate characterization of the fiber optic system's apability. This is. Recommendation ITU-T G.
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