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

Abstract

Abstract-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 slowwave 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 . 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.

Analysis of Hybrid-Integrated High-Speed Electro-Absorption Modulated Lasers Based on EM/Circuit Co-simulation

“…It should be observed that both the amplitude and the phase are accurately captured in the EM simulations as compared to measurements up to 65 GHz. This verifies the EML intrinsic circuit model developed in [8]. Given this EML circuit model it is possible to investigate the EML embedding circuitry.…”

“…Instead a lumped smallsignal equivalent circuit model for the MQW stack in the EAM and the laser junction parts are included into the HFSS EM simulation. This can be accomplished by using lumped RCL-boundary conditions available in the Ansoft HFSS simulator [8]. For the EAM junction typical values for the junction capacitance Cs and dynamic photocurrentresistance Rph are substituted into the HFSS simulation domain, while a single capacitor Claser is substituted for the laser MQW in a similar manner.…”

“…Only the HFSS simulation results for the part containing the wire-bonded integrated EML structure needs to be represented with an equivalent circuit model. Fortunately the lumped equivalent circuit model for the monolithically integrated EML has already been developed in our previously work [8]. In order to fit the HFSS simulation results this equivalent circuit model needs to be embedded with small wire-bond inductors and short 50Q microstrip lines representing the line parts located within the reference planes shown in Fig.…”