光纤色散效应对脉冲展宽的影响  

Effect of fiber dispersion on pulse width

作　　者：宋扬[1] 王丽[1] 

机构地区：[1]北京工业大学应用数理学院,北京100022

出　　处：《激光技术》2008年第6期568-571,共4页Laser Technology

基　　金：北京市自然科学基金资助项目(4062008)

摘　　要：为了研究光通信系统中光纤色散特性对通信系统传输性能的影响,基于单模光纤和多模光纤的色散特性,采用数值模拟计算的方法,对脉冲展宽、光纤内部的偏振模色散、色度色散、波导色散和模间色散的物理机制进行了分析,分别得到了折射率n=1.516和n=1.458的标准单模光纤经过10km传输距离后色散导致脉冲展宽的结果,比较了传输波长在850nm和1310nm时多模光纤的色散效应,通过对不同光源LD(Δλ=1nm)和LED(Δλ=70nm)的比较,分析了光谱宽度对脉冲展宽的影响。结果表明,纯石英光纤在系统传输波长为1.27μm处群速度色散等于0;折射率渐变多模光纤工作在常见的850nm以及1310nm通信窗口时,其模内色散表现为负色散;色度色散和模间色散引起的脉冲展宽随光纤的数值孔径、材料折射率和光源光谱线宽的增大而增大。In order to study the influence of dispersion on the information transfer capacity of the communication system, the mechanism of all kinds of dispersion for single-mode and muhimode fibers, such as polarization mode dispersion, material dispersion, wave leading dispersion and mode dispersion, was studied by means of simulation. The expanded pulse width induced by dispersion in standard fibers whose refractive index n = 1. 516 and n = 1. 458 respectively was obtained after propagating 10km distance. The dispersion effect for muhimode fibers with the propagation wavelength as 850nm and 1310nm respectively was compared. The effect of the spectrum width of the different laser sources, such as LD（ △γ = 1 nm） and LED（ △γ = 70nm） , on the pulse width was compared. It shows that the group velocity dispersion group velocity dispersion is 0 when the propagation wavelength of the system is 1.27 um for a pure silica fiber, the intra-modal dispersion becomes abnormal dispersion when the graded-index muhimode fiber is in the propagation window of 850nm or 1310nm and that the expanded pulse width induced by the chromatic dispersion and modal dispersion would increase with the numerical aperture, refractive index and the spectrum width of the laser source.

关 键 词：光纤光学 脉冲展宽 群速度色散 偏振模色散 

分 类 号：O437[机械工程—光学工程] TN929.11[理学—光学]