Research on Germanium Photodetector with Multi-Mode Waveguide Input

In this work, a vertical N-I-P germanium (Ge) photodetector (PD) with multi-mode waveguide input is presented. The fabricated devices exhibit low dark current of 10 nA at bias −1 V, and high responsivity exceeding 0.75 A/W over the wavelength range from 1270 to 1350 nm. High-frequency characteristics measurements show that has 3 dB opto-electrical (OE) bandwidth 23 GHz under −3 V bias, which can be further improved by optimization configuration. A 50 Gb/s clear eye diagram non-return-to-zero (NRZ) modulation format demonstrated. By using single-mode excitation source, used simulate light coming division multiplexing (WDM) devices, sweeping its position, it shown utilized in WDM receiver achieve both flat-top passband.