I need help with the fiber function

Hello, I am trying to use the fiber optic function, to model a sinusoidal signal (and not a Gaussian pulse, as is usually done) I am doing it to try to understand the concept of electronic compensation. I need you to graph the two signals for me, (obviously one smaller than the other) but when I execute my code, the signal that Hd returns, only appears in the positive part and not in the negative part.

this is what i should throw:

and this is what it throws at me:

this is the code

A =2; %Amplitud

f = 100; %Frecuencia fundamental

Tb=1/f;

n_bits=4;

w=2*pi*1/Tb; %Frecuencia angular

Fs=64/Tb; %Frecuencia de Muestreo

Ts=1/Fs; %Tiempo de bit

Nmpb=(Tb/Ts)+1; %Número de muestras por bit

Nmps=Nmpb*n_bits; %Número de muestras de toda la secuencia

b2 = -21.6*(1e-12^2)/1e3;

b3 = 0.117*(1e-12^3)/1e3;

Dz = 10e3;

t=0:Ts:(Nmps-1)*Ts;

x=A*sin(2*pi*f*t);

x1=x+2; %GENERA SEÑAL

Hd=exp(j*0.5*b2*Dz*w.*w-j*b3*w.*w.*w*Dz/6);

AouF=fftshift(fft(x1)).*Hd;

Aou=ifft(fftshift(AouF));

plot(t,x,'b',t,abs(Aou),'g')