请利用 Matlab 绘制光纤结构,标注纤芯和包层折射率n1和n2,并模拟光纤传输光信号(含阶跃光纤和渐变光纤两种类型)?注:在图中显示各自的学号和姓名。 Please draw the optical fiber structure by using MATLAB , label the core and cladding refractive index n1 and n2, and simulate optical fiber transmission signal (including step optical fiber and gradient optical fiber)? Note: the student number and name should be shown in the picture.