apodization equation in optigrating script

[aasif bashir dar]

hi all,

i am currently facing problem in writing apodization function equations in the optigarting script…

the apodization functions mentioned in papers are gennerally applied for -L/2 <z< +L/2

where L is grating length and z is the variarable that very along the Length…

but apodization functions in the optigarting can be writwn only for 0<z<L…

what to do…
i require equations that are valid for range 0<z<L
with regards

[aasif bashir dar]

with regards
The non-uniform (chirped and apodized) grating [1] is divided into Number of Segments uniform gratings. The coupled mode theory is used to calculate the scattering matrix of each uniform segment, and the spectral response of the whole grating is found by connecting the uniform segments using the transfer matrix theory. The apodization functions Gaussian and Hyperbolic tangent are defined with the following parameters:
Gaussian
exp{-ln2[(2.(z-L/2)/s.L]^2}
Hyperbolic tangent
tanh (s.z/L).tanh(s.(1-z/L))+1-tanh^2(S/2)
When the parameter Apodization function is user-defined, you provide a file with the data describing the apodization. The input file is formatted containing two items per line — the length in μm and the apodization value.

but i can not find others for the range of zero to length of the FBG

looking for the response..
with regards

[Steve Dods]

You could simply make a substitution in the equation. Write z for the OptiGrating coordinate and x for the coordinates used in the papers. Let x = z – L/2. For OptiGrating, 0 < z < L, and in those papers -L/2 < x < L/2. Then the Gaussian is exp{-ln2[(2.(x)/s.L]^2}. And so on…

[aasif bashir dar]

thanks for reply

[SAHIL SINGH]

Hi all,

A very meaningful discussion onapodization equation in optigrating script…

Regards
Sahil Singh

[Manoj Kumar]

The non-uniform (chirped and apodized) grating [1] is divided into Number of Segments uniform gratings. The coupled mode theory is used to calculate the scattering matrix of each uniform segment, and the spectral response of the whole grating is found by connecting the uniform segments using the transfer matrix theory. The apodization functions Gaussian and Hyperbolic tangent are defined with the following parameters:
Gaussian
exp{-ln2[(2.(z-L/2)/s.L]^2}
Hyperbolic tangent
tanh (s.z/L).tanh(s.(1-z/L))+1-tanh^2(S/2)
When the parameter Apodization function is user-defined, you provide a file with the data describing the apodization. The input file is formatted containing two items per line — the length in μm and the apodization value.

but i can not find others for the range of zero to length of the FBG

looking for the response..
with regards

[Marwa Ramadan]

Dear all,
I would like to ask about user defined chirp function in fiber Bragg grating of Optisystem.
I have to provide a file with the data describing the chirp. The input file is formatted containing two items per line – the length in um and the chirp value in um.
I may not understand well the second column, so can anyone help me to understand that?

I am working now on the attached paper.
I have a problem in linking between matlab and optisystem, but I am leaving this problem now to concentrate on solving chirp function problem firstly.
what I am doing is to take the results from matlab workspace and put them in “.dat file” then use user defined file.
I created the attached Matlab “.m file”, took the results from matlab workspace, and put them in the attached “.dat file”.
why does not the expected result appear? is there any help to understand the mistake in that?

[Marwa Ramadan]

mail 2 of 2
FYI
this is the “.dat file”. I just convert it to “.txt file” to can upload it, but you can reconvert it to can use”.
Thanks and Regards.

[Marwa Ramadan]

Why doesn’t anyone reply? Do you want me to put my question in a separate post?

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