On-chip germanium photodetector with interleaved junctions for the 2-µm wave band.
Opt Lett
; 49(4): 1085-1088, 2024 Feb 15.
Article
en En
| MEDLINE
| ID: mdl-38359259
ABSTRACT
Recently, the 2-µm wave band has gained increased interest due to its potential application for the next-generation optical communication. As a proven integration platform, silicon photonics also benefit from the lower nonlinear absorption and larger electro-optic coefficient. However, this spectral range is far beyond the photodetection range of germanium, which places an ultimate limit for on-chip applications. In this work, we demonstrate a waveguide-coupled photodetector enabled by a tensile strain-induced absorption in germanium. Responsivity is greatly enhanced by the proposed interleaved junction structure. The device is designed on a 220-nm silicon-on-insulator and is fabricated via a standard silicon photonic foundry process. By utilizing different interleaved PN junction spacing configurations, we were able to measure a responsivity of 0.107â
A/W at 1950â
nm with a low bias voltage of -6.4â
V for the 500-µm-long device. Additionally, the 3-dB bandwidth of the device was measured to be up to 7.1â
GHz. Furthermore, we successfully achieved data transmission at a rate of 20â
Gb/s using non-return-to-zero on-off keying modulation.
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MEDLINE
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En
Revista:
Opt Lett
Año:
2024
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Article