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Waveguide-integrated, ultralow-energy GeSi electro-absorption modulators

Abstract

Waveguide-integrated photonic modulators are crucial devices when encoding optical signals for electronic–photonic integration on silicon1,2. Silicon photonic modulators based on the free carrier plasma dispersion effect3 have undergone significant development in recent years4,5,6,7,8,9,10, reaching speeds of 40 Gbit s–1 (ref. 7). Some issues yet to be resolved include the large size and the relatively high energy consumption of silicon Mach–Zehnder interferometer modulators, and the susceptibility to fabrication errors as well as a limited operation wavelength range of 1 nm for silicon microring modulators. We demonstrate the first waveguide-integrated GeSi electro-absorption modulator on silicon with a small active device area of 30 µm2, a 10-dB extinction ratio at 1,540 nm, an operating spectrum range of 1,539–1,553 nm, ultralow energy consumption of 50 fJ per bit, and a 3-dB bandwidth of 1.2 GHz. This device offers unique advantages for use in high-performance electronic–photonic integration with complementary metal oxide semiconductor circuits.

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Figure 1: Structure of the waveguide-integrated GeSi EA modulator.
Figure 2: Performance of the GeSi EA modulator.
Figure 3: Dynamic EO response of the device in the frequency range of 10 MHz to 10 GHz with a dynamic driving voltage (Vpp) of 3 V.

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Acknowledgements

This research was sponsored under the Defense Advanced Research Projects Agency's (DARPA) EPIC program supervised by J. Shah in the Microsystems Technology Office (MTO) under contract no. HR0011-05-C-0027. The authors would like to thank K. Wada and D. Pan for their early contributions to this work, and D. Gill from Alcatel-Lucent Bell Laboratories and S. Akiyama from Fujitsu Laboratories for helpful discussions.

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Correspondence to Jifeng Liu.

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Liu, J., Beals, M., Pomerene, A. et al. Waveguide-integrated, ultralow-energy GeSi electro-absorption modulators. Nature Photon 2, 433–437 (2008). https://doi.org/10.1038/nphoton.2008.99

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