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 & BULL;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.

Automated summary

This study investigates the modulation responses of Fabry-Perot Ge-on-Si lasers through modeling and simulations. The relationship between the 3 dB bandwidth and structure parameters such as poly-Si cladding thickness, Ge cavity width and thickness, and minority carrier lifetime is studied. It is predicted that after optimizing the Ge laser structure with a defect limited carrier lifetime of 1 ns, a 3 dB bandwidth of 33.94 GHz can be achieved at a biasing current of 270.5 mA. The simulated eye diagrams show a stable eye-opening window at 20 Gb/s NRZ. Improving the minority carrier lifetime to 10 ns would reduce the threshold current to 6.85 mA and increase the 3 dB bandwidth to 36.89 GHz.