Optical Frequency Comb Generation by Interfering Multiple Lasers in Mach-Zehnder Modulator

One of the promising techniques to generate optical frequency comb (OFC)(COMB) is based on the interference of laser signals in a Mach-Zehnder modulator (MZM). The modulator is asymmetrically dual driven by two electrical sinusoidal signal sources with two different frequencies. The OFC is characterized by high level of spectral flatness, high Optical Signal To Noise Ratio (OSNR), and large number of wavelengths. In this paper, the OFC generated by applying multiple laser sources to a single dual arm MZM which is driven by two sinusoidal signals. The output of the MZM is developed to provide a large number of equally spaced optical wavelengths with small power deviation. Various aspects of the generated optical signal are controlled by the number of input lasers and the parameters of modulated electrical signals. The simulation results show that the proposed OFC achieves high number of wavelengths (lines) and spectral flatness (up to flatness 20 dBm) compared to existing generation schemes.