Optimization of integrated electro-absorption modulated laser structures for 100 Gbit/s ethernet using electromagnetic simulation

In this paper three options for very-high bit rate integrated electro-absorption modulated laser (EML) structures are investigated using electromagnetic simulation. A physics based distributed equivalent circuit model taking the slow- wave propagation characteristics of the modulation signal into account is proposed for the electro-absorption modulator (EAM) electrode arrangement. This model makes it possible to apply an EM/circuit co-simulation approach to estimate the electrical to optical transmission bandwidth for the integrated EML. It is shown that a transmission bandwidth of 70 GHz seems feasible with the investigated EML structures if the driving impedance is reduced to 25 Omega. It is also shown that the influence of electromagnetic cross-talk between components can be neglected in the estimation of the transmission bandwidth even in the case of very short separation zones. Finally, a slight decrease in transmission bandwidth is observed for an EML structure without ground pillars.