Directly Modulated Laser Intrinsic Parameters Optimization for WDM Systems

Direct modulation schemes have involved increased attention during the past few years because of their intrinsic simplicity and cost-effectiveness, especially when applied to WDM metro and access networks. However, the output power waveform from a directly modulated laser is not an exact replica of the current modulation and its instantaneous optical frequency varies with time depending on the changes in the optical power (an effect also known as frequency chirp). In this work, using an Optical Communication System Design Software, we studied a directly modulated WDM 2.5 Gb/s system. We have demonstrated that transmission performance depends strongly on DML characteristics. Furthermore, simulation results provided further details about the effects of DML type (adiabatic or transient chirp dominated) as well as the effects of the optical output power. These details can provide useful design guidelines for the design of a WDM metro network.