Generation of electro-optic frequency combs with optimized flatness in a silicon ring resonator modulator

Abstract: The flatness of electro-optic frequency combs (EOFCs) generated in a single silicon ring resonator modulator (RRM) is optimized by employing harmonic superposition of the radio-frequency driving signal. A differential evolution algorithm is employed in conjunction with a simplified model of the RRM for offline optimization of the amplitudes and phases of harmonic driving signals and the operating point of the RRM. The optimized driving signals are then applied to a silicon RRM. EOFCs containing 7 and 9 lines are synthesized with a power imbalance between the lines of 2.9 dB and 5.4 dB, respectively, compared to 9.4 dB for an optimized 5-line comb generated from a single sinusoidal driving signal.