多模光纤RoF系统的模式噪声分析

为改善短距离、低成本多模光纤RoF链路性能,需要对多模光纤中的重要限制因素—模式噪声进行分析,并寻找降低模式噪声影响的方案。首先分析了模式噪声的产生条件,建立了多模光纤RoF链路中模式噪声的数学模型,通过模型可以得出激光器频率啁啾越大、调制深度越低、光电二极管检测面积越小输出射频信号载噪比越小。可以通过降低激光器频率啁啾,增大调制深度和光电二极管检测面积来改善系统性能。

Analysis of Modal Noise in Radio over Multimode Fiber Systems

In order to improve the performance of short-range cost-effective radio over multimode fiber links,modal noise,as an important limiting factor in multimode fiber,should be analyzed,and the scheme to reduce this noise is required.Causes and theoretical model of modal noise in radio over multimode fiber systems are presented.From the model,it can be seen that the CNR of output RF signal would become lower with the increasing of frequency chirp,the optical modulation index and the detecting area of photodiode be reduced.Systems performance can be improved by reducing frequency chirp,increasing optical modulation index or enlarging detecting area of photodiode.