Suppression of modal noise of a graded-index multimode fiber in a white-light interferometric system

摘要

Abstract: A study on the effect of modal noise induced by themodal coupling effect in a graded index multimodefiber, illuminated by a light source with a tunablecoherence length was carried out. It has been shownthat the value of the signal-to-noise (S/N) ratio in aninterferometric system could be reduced by theperturbation-induced modal noise if in the coherencelength is in the region of 30 to 80 $mu@m. As thecoherence length increase, the S/N ratio will reducecorrespondingly. However, when the value of thecoherence length is in the region of 80 $mu@m andupward, the value of the corresponding reduction in S/Nratio was seen to vary only over a very small range.!5