Monolithic vertical integration of VCSEL and RCEPD for bidirectional optical interconnects

In this letter, we demonstrate the monolithic vertical integration of vertical-cavity surface-emitting laser (VCSEL) with resonant cavity enhancement photodetector (RCEPD) for the application to bidirectional optical interconnect. Based on the optimal designed structure, the monolithic integrated device can realize optical decoupling and electrical isolation between its VCSEL unit and RCEPD unit. The VCSEL unit exhibits a threshold current of 1.65 mA, a slope efficiency of 0.58 W/A and 3 dB bandwidth of 12.8 GHz. Regarding the RCEPD unit, the width of its absorption quantum efficiency spectrum is 8 nm with a quantum efficiency of higher than 50%. The 3 dB response bandwidth of the RCEPD unit can be up to 65.7 GHz.