InP-based membrane photodetector for optical interconnections on CMOS ICs

We demonstrate a compact photodetector suitable for photonic interconnections on electronic ICs. In such applications, the InP-based optical sources and detectors are linked via Si photonic waveguides in an interconnection layer on top of the CMOS circuitry. The photonic device processing is compatible with Si wafer scale fabrication steps, which guarantees compatibility with future IC manufacturing. In our approach, an InP membrane waveguide is used to couple the light out of the interconnection layer and carry it towards the detector absorption region. A responsivity of 0.45 A/W and an electrical frequency response 3-dB cut-off point at 15 GHz were measured.