Monolithic integration of VCSEL and coupled cavity RCEPD for short-reach single-fiber bi-directional optical interconnects

In this paper, we propose a monolithic integration of vertical-cavity surface-emitting laser (VCSEL) and coupled cavity resonant cavity enhancement photodiode (ccRCEPD). Based on this structure, a couple of matched chips is designed for single fiber bidirectional optical interconnects. That type of integration can easily put VCSEL and (photodiode) PD into one package, which not only reduces the costs of the device packages and even cut the costs of the optical system like beam splitter, but also can save the space in optical transceiver to make it tight. These chips' VCSELs show a threshold current of 1.6 mA and 1.7 mA, and a slope efficiency of 0.74 W/A and 0.97 W/A. VCSELs' modulation bandwidth is 9.5 GHz and 11.0 GHz, and PDs' response bandwidth is 10 GHz. Furthermore, the modulation bandwidth can be higher if the material of the multiple quantum wells (MQWs) is transformed GaAs/AlGaAs to InGaAs/AlGaAs. And by optimizing, the 3dB bandwidth of PD will be higher. Graphical abstract:

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