Hi Moataz,
You have an interesting project! Unfortunately, I didn’t make any projects myself, but some nice work has been done in this field. Damian sent you a valuable resource about microwave frequency octupling generation. I’m attaching you two interesting papers according to your question. First describes the generation of a flat optical frequency comb (OFC) using an EAM and two cascaded PM (spectral manipulation of comb lines is the main idea).