Hi all
I am trying to calculate and draw the group delay of contradirectional bragg grating.
I already calculated the reflectance and got its phase as shown in the figure.
when I differentiate the phase i got unlogical spikes like that figure

while the correct plot is shown in Yariv book as the following figure (trace denoted by taw)
to differentiate i tried two functions diff and gradient and both gave me the same spikes (which is wrong). These are the lines i used in matlab:
Reflection=S11;
R=abs(Reflection).^2;
R_phase2=unwrap(angle(Reflection));
phase_lambda=lambda*1e9;
dphasedlambda1 =-phase_lambda.^2./(2*pi*c).*( gradient(R_phase2) ./ gradient(phase_lambda));
dphasedlambda2 =-phase_lambda(1:end-1).^2./(2*pi*c).*( diff(R_phase2) ./ diff(phase_lambda));
Any help with that problemHi all
I am trying to calculate and draw the group delay of contradirectional bragg grating.
I already calculated the reflectance and got its phase as shown in the figure.
when I differentiate the phase i got unlogical spikes like that figure

while the correct plot is shown in Yariv book as the following figure (trace denoted by taw)
to differentiate i tried two functions diff and gradient and both gave me the same spikes (which is wrong). These are the lines i used in matlab:
Reflection=S11;
R=abs(Reflection).^2;
R_phase2=unwrap(angle(Reflection));
phase_lambda=lambda*1e9;
dphasedlambda1 =-phase_lambda.^2./(2*pi*c).*( gradient(R_phase2) ./ gradient(phase_lambda));
dphasedlambda2 =-phase_lambda(1:end-1).^2./(2*pi*c).*( diff(R_phase2) ./ diff(phase_lambda));
Any help with that problem Hi all
I am trying to calculate and draw the group delay of contradirectional bragg grating.
I already calculated the reflectance and got its phase as shown in the figure.
when I differentiate the phase i got unlogical spikes like that figure

while the correct plot is shown in Yariv book as the following figure (trace denoted by taw)
to differentiate i tried two functions diff and gradient and both gave me the same spikes (which is wrong). These are the lines i used in matlab:
Reflection=S11;
R=abs(Reflection).^2;
R_phase2=unwrap(angle(Reflection));
phase_lambda=lambda*1e9;
dphasedlambda1 =-phase_lambda.^2./(2*pi*c).*( gradient(R_phase2) ./ gradient(phase_lambda));
dphasedlambda2 =-phase_lambda(1:end-1).^2./(2*pi*c).*( diff(R_phase2) ./ diff(phase_lambda));
Any help with that problem group delay, bragg, phase differentiation MATLAB Answers — New Questions

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