High-Speed 1550 nm Photoconductive Detector With Plasmonic Micro-Grating Electrodes

The In this letter, we propose a high-speed photoconductive detector with micro-sized plasmonic grating electrodes that support coupled plasmonic modes. The photoconductive InGaAs:Be layer was grown on InP substrate at 250°C, on which the electrode parameters were optimized and fabricated. Both theoretical and experimental results demonstrate that the plasmonic effect was successfully excited by the micro-grating, and the responsivity was increased by 12 times as compared with the detectors without grating. An optical heterodyne system measurement showed a 3-dB bandwidth of at least 50 GHz. Furthermore, the structural error tolerances of the proposed device were studied, revealing significant improvement in fabrication stability.