Theoretical study of small signal modulation behavior of Fabry-Perot germanium-on-silicon lasers

This work investigated the modulation responses of Fabry–Perot Ge-on-Si lasers by modeling and simulations. The 3 dB bandwidth dependence on the structure parameters such as poly-Si cladding thickness, Ge cavity width and thickness, and minority carrier lifetime were studied. A 3 dB bandwidth of 33.94 GHz at a biasing current of 270.5 mA is predicted after Ge laser structure optimization with a defect limited carrier lifetime of 1 ns. The eye diagrams simulated show a stable eye-opening window at 20 Gb·s −1 NRZ. The improvement to 10 ns minority carrier lifetime would reduce the threshold current to 6.85 mA, and increase the 3 dB bandwidth to 36.89 GHz.