基于超短脉冲边带（Kelly sidebands)结构测量光纤色散的方法改进
毕业论文关键词：光纤色散 Kelly 边带 线性拟合
Improved Method based on Ultrashort Pulse Sideband(Kelly Sidebands) Measuring Fiber Dispersion Structure
Abstract：This thesis proposes a method for measurement of fiber dispersion. That is,using the effect of spectral sidebands to measure the value of fiber dispersion inpassively mode-locked erbium-doped fiber lasers, and the value is more accurate. In theexperiment, by continuously changing the cavity length, we find that the longer thelength of the cavity, the more the number of sidebands. Therefore, we choose the cavitylength of 103 m to calculate the dispersion of the fiber. When we analyze the data, thecenter wavelength of the spectrum are 1558.15 nm and 1574.4 nm, respectively. We cangain data of sideband order and corresponding wavelength offset from the spectrum. Weplot three lines by doing the linear least squares fitting, they are the one for the negativesideband order only, the one for positive sideband order only, and the one for allsideband order to the corresponding the square of sideband wavelength offset. Thecorrelation coefficient of the fitting based on the negative sideband order only or thepositive sideband order only are both better than that based on the sideband order fromnegative to positive, that is, the former is closer to the true value. And the slopes of thefitting lines are different which suggest that the dispersion parameter indeed depends onwavelength. Combined the equation of sideband with the formula of the fitting line, wegive out the more accurate method to calculate the dispersion of fiber.
Keywords: fiber dispersion Kelly sidebands linear fitting
目录
1绪论 1
1.1 光纤.1
1.1.1光纤的定义、原理以及结构. 1
1.1.2光纤的发展大事记. 2
1.1.3光纤的种类. 3
1.1.4 传输的优点.3
1.1.5光纤的制备和施工方法. 4
1.1.6光纤的应用. 4
1.2 光纤通信.4
1.2.1光纤通信的定义. 4
1.2.2光纤通信的原理及工作过程. 4
1.2.3光纤通信的设备组成及技术应用. 4
1.3 光孤子通信.5
1.3.1光纤的损耗和补偿. 5
1.3.2光纤的色散. 6
1.4 选题内容及其意义.7
2实验部分 8
2.1 实验原理.8
2.2 实验装置.9
2.3 实验操作10
2.4 实验分析和讨论12
3.结论 14
1 绪论1.1光纤1.1.1 光纤的定义、原理以及结构光导纤文简称为光纤，使用玻璃或者塑料作为原材料制作而成，可以用来进行光传导。由于传播介质不同，光速一般是不同的，所以当光从一种介质射向不同介质时，折射和反射现象就会出现在两种介质的分界面。并且，入射角增大时，折射角也随着入射角增大而增大。当入射角大于或者等于临界角度时，折射光就会消失，就只剩下反射光，这种现象叫做光的全反射[1]。光纤被用来传播信息就是运用了上述原理。全反射的原理图 所示。