what is the matlab code for ploting dispersion against wavelength (for chromatic dispersion)?

I would like to get some matlab codes to draw graphs showing chromatic disperion

[PRADEEP TOMAR]

clc; %please correct it,i am not getting the exact plot
clear all;
close all;
c=3*10^8;
neff=1.46;
dn= 1.2*10^(-3);
 z= 0.5*10^(-3);
xa=5*10^(-3);
ya=1.28*10^(-6):1*10^(-10) :1.29*10^(-6);
lambdab= 1.286*10^(-6);
gz = 0.55+ 0.45.*cos((z.*pi)./xa) ;
D = (4.*pi.*c.*neff.*(lambdab./(2.*neff)).*(pi.*dn.*gz).^2)./((ya.^2).*((2.*neff.*gz.*(lambdab./(2.*neff))).^2 -(pi.*dn.*gz).^2 ).^1.5);
plot(ya,imag(D));

Answer 1

[Ahmed]

what is the matlab code for ploting dispersion against wavelength (for chromatic dispersion)?