A new technique for creating flattened optical frequency comb generator by utilizing multi-stages of optical modulators

In this article, we demonstrate an optical frequency comb generator employing two stages of the optical modulators. Where the first stage consists of two electro-absorption (EA) modulators and the second stage built by the phase (PM) and amplitude (AM) modulators, respectively. By changing the chirp factor of the EAs through the first stage, high number of the comb lines will be generated. As a consequence of spectral ripple (i.e., the spectral flatness within 1 dB and or less than 1 dB), the second stage using the cascaded PM and AM will be employed. Thus, higher number of comb lines with the best spectral flatness will be obtained. Mathematical modeling and the simulation using Optisystem software for the proposed setup are achieved through this work. By changing the chirp factor from 1 to 15, 76 to 127 comb lines were generated through the first stage. Furthermore, 120 comb lines at the frequency spacing of 25 GHz within the spectral flatness of <= 1 dB was generated from the second stage.