High-performance Ge/Si electro-absorption optical modulator up to 85°C and its highly efficient photodetector operation

• Published in: Optics express Vol. 31; no. 6; pp. 10732 - 10743
• Main Authors: Fujikata, Junichi, Noguchi, Masataka, Katamawari, Riku, Inaba, Kyosuke, Ono, Hideki, Shimura, Daisuke, Onawa, Yosuke, Yaegashi, Hiroki, Ishikawa, Yasuhiko
• Format: Journal Article
• Language: English
• Published: United States 13.03.2023
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.484380

We studied a high-speed Ge/Si electro-absorption optical modulator (EAM) evanescently coupled with a Si waveguide of a lateral p-n junction for a high-bandwidth optical interconnect over a wide range of temperatures from 25 °C to 85 °C. We demonstrated 56 Gbps high-speed operation at temperatures up to 85 °C. From the photoluminescence spectra, we confirmed that the bandgap energy dependence on temperature is relatively small, which is consistent with the shift in the operation wavelengths with increasing temperature for a Ge/Si EAM. We also demonstrated that the same device operates as a high-speed and high-efficiency Ge photodetector with the Franz-Keldysh (F-K) and avalanche-multiplication effects. These results demonstrate that the Ge/Si stacked structure is promising for both high-performance optical modulators and photodetectors integrated on Si platforms.