Increasing responsivity-bandwidth margin of germanium waveguide photodetector with simple corner reflector

Chih-Hsien Lin, Ding-Wei Huang, Tien-Tsorng Shih, Hao-Chung Kuo, Shu-Wei Chang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The external bandwidth of germanium waveguide photodetectors (PDs) decreases with the device length due to the load and parasitic effects even if the internal one is less affected. Shortening PDs raises the external bandwidth but lowers the responsivity, introducing a trade-off between the two figures of merits. Here, we present a scheme of waveguide PDs based on total internal reflections of corner reflectors. The reflector can be easily fabricated with the standard photolithography at the end of PDs to efficiently reflect optical power back to germanium for additional absorption, allowing for further size reduction. The structure may render the optimization of PDs more flexible. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Original languageEnglish
Pages (from-to)10364-10373
Number of pages10
JournalOptics Express
Issue number7
StatePublished - 29 Mar 2021

Cite this