Electroabsorption Modulated Laser With High Immunity to Residual Facet Reflection

We report on the design for an electroabsorption-modulated laser (EML) that can provide a high immunity to the optical signal reflected from its output facet without any fabrication complexity and performance compromise. In particular, we theoretically investigate the effects of residual facet reflection on the static and dynamic performances of the high-speed EMLs. For this analysis, an accurate and consistent time-domain transfer-matrix-based laser model is developed. Based on this model, we perform the steady-state and large-signal analyses for the EML with finite facet reflectivities. The simulation result indicates that the EML with a high-gain compression factor is capable of reducing the power fluctuation and facet reflection-induced chirp under large-signal modualtion. Thus, it is desirable to design for increasing the damping of a distributed feedback (DFB) laser to realize the EML with a high immunity to this facet reflection. The simulation also shows that the effect of this facet reflection strongly depends on the phase condition between the optical signal reflected from the output facet and the light emitted from the DFB laser and, in particular, at that specific phase condition, a clear eye opening appears even at the relatively high-output facet reflectivity (i.e., $R_{f}=1\%$).