Simulated Performance Analysis of an Optical Frequency Comb in a WDM System

This paper presents the research work for a proposed novel scheme for generating a flat and equally spaced optical frequency comb using a simulated layout using Optisystem. Three pump sources at 1 nm wavelength apart are injected along with a 25 GHz RF signal having different amplitudes into a cascade of Dual-Drive Mach-Zehnder Modulator and Electro-Absorption Modulator and multiple highly nonlinear fiber loops. The initial scheme is using Four Wave - Mixing and yields a comb of 27 lines with uneven gain and a 6 dBm power deviation. After characterizing the response by exploring critical parameters such as pump power, frequency spacing, dispersion effect, Erbium Doped Fiber Amplifier and DC bias of the modulators, the researchers were able to reduce the power deviation down to 2 dBm at the expense of some comb lines. This final optimized scheme was then evaluated for a preliminary Wavelength Division Multiplexing setup having only five channels/modes at 10 Gb/s for a channel length of 1 km. Each of the received de-multiplexed channels was evaluated through recorded data in the form of Bit Error Rate and Quality-factor and the final results are shown to be quite promising.