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High-speed detection at two micrometres with monolithic silicon photodiodes


With continued steep growth in the volume of data transmitted over optical networks there is a widely recognized need for more sophisticated photonics technologies to forestall a ‘capacity crunch’1. A promising solution is to open new spectral regions at wavelengths near 2 μm and to exploit the long-wavelength transmission and amplification capabilities of hollow-core photonic-bandgap fibres2,3 and the recently available thulium-doped fibre amplifiers4. To date, photodetector devices for this window have largely relied on III–V materials5 or, where the benefits of integration with silicon photonics are sought, GeSn alloys, which have been demonstrated thus far with only limited utility6,7,8,9. Here, we describe a silicon photodiode operating at 20 Gbit s–1 in this wavelength region. The detector is compatible with standard silicon processing and is integrated directly with silicon-on-insulator waveguides, which suggests future utility in silicon-based mid-infrared integrated optics for applications in communications.

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Figure 1: SEM images of the photodetector.
Figure 2: Steady-state photodiode current measurements.
Figure 3: Eye diagrams for a 1-mm-long detector operating at a wavelength of 1.96 μm.
Figure 4: The small signal frequency response at a wavelength of 1,550 nm.


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The authors thank D. Deptuck and J. Zhang at CMC Microsystems as well as L. Chrostowski of the SI-EPIC programme for facilitating device fabrication, the Canadian Centre for Electron Microscopy for SEM imaging work, C. Brooks for measurement assistance and the Natural Sciences and Engineering Research Council of Canada. Funding from the Engineering and Physical Sciences Research Council in the UK also supported this work (to support the MIGRATION and Silicon Photonics for Future Systems projects). G.M. acknowledges support from the Royal Society through his Royal Society Research Fellowship. G.R. is a Royal Society Wolfson Research Merit Award holder and acknowledges the Wolfson Foundation and the Royal Society for funding the award. The authors thank M. Nedeljkovic for discussions and assistance with device simulation, Z. Li for use of his custom-built TDFA, S. Alam for laser diodes and R. Slavik for measurement assistance and discussions.

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Authors and Affiliations



J.A., D.T. and L.S. performed the experiments. A.P. and G.R. were responsible for the measurement systems. J.A. and A.K. designed the devices and wrote the manuscript. G.M. and D.T. discussed the results and assisted with manuscript preparation. P.J. contributed to the device and experimental design. A.K. and G.M. supervised and coordinated the project. All authors contributed to writing the paper.

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Correspondence to Jason J. Ackert.

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The authors declare no competing financial interests.

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Ackert, J., Thomson, D., Shen, L. et al. High-speed detection at two micrometres with monolithic silicon photodiodes. Nature Photon 9, 393–396 (2015).

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