FDTD help

i try to simulate optical fiber in FDTD by BOR-FDTD and i want to put a source in one side of optical fiber
(z=0).
i need to tell me which method i use to put source
i try to use TF/SF but the results i get is not good
please help me . if any one have acode like this by TF/SF in matlab or c++
please give it to me .



thanks