L=linspace(0,4.5e-3,1000);dltn=1e-3;V=2.4;lammda=1550e-9;C=pi./lammda.*(1-1/(V.^2)).*dltn;R=tanh(C.*L).^2;figure(1);plot(L,R);hold on;L=linspace(0,4.5e-3,1000);
