Fiber Bragg Grating Simulation - Optical Communication

Hello all,

I am working on a simple project where I have to plot the reflection spectrum for various Fiber Grating with uniform grating and different lengths. I am good with the theory part of it but for simulating, I have no idea how to input the parameters and the code in MATLAB. After much research, the simulation results are always provided but not the code. If someone can point me in the right direction it will be helpful.

Thanks
Simardeep Gill