International intercomparison of attenuation in fiber optic systems: multimode fiber and LED-based comparison

The result of an international comparison of incremental attenuation steps of a multimode fiber-optics attenuator bat 850 nm is reported. In multimode systems, the measurement value varies with such measuring conditions as the light source spectrum and the spatial distribution of light at launching into the fiber. Therefore, a specially designed step attenuator was used as the transfer standard, and reference conditions were set up. The maximum differences among the mean values of the measurements were less than 0.03 dB/10 dB. The result shows the possibility of using a step attenuator as an attenuation standard in multimode fiber-optic systems under specific reference conditions