Hi,
Maybe I am misinterpreting what you mean by put the codeword on FBG, but I think my earlier reply answered that. If you take a look at the example file that comes with OptiSystem “FE-OCDMA 7 Users.osd” you will see that the first user has codeword: 10101010 which means we need to remove the spectral content belonging to wavelength2, wavelength4, wavelength6 and wavelength8. Using a FBG centered at the undesired wavelength you can reflect only that wavelength, so after placing 4 in succession the four wavelengths can be removed.
I have attached some screenshots of the project to hopefully make it clearer.
I am not familiar with MQC, but I believe once you can find the codewords for the different users then the procedure of placing the FBG’s is the same. Let me know if anything is unexplained!
Regards