Electro-absorption optical modulator using
dual-graphene-on-graphene configuration
Shengwei Ye,
*
Zishuai Wang, Linfeng Tang, Yali Zhang, Rongguo Lu, and Yong Liu
State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information,
University of Electronic Science and Technology of China, Chengdu, 610054, China
*
swye1988@gmail.com
Abstract: An electro-absorption optical modulator based on
dual-graphene-on-graphene configuration is presented and investigated. Four
graphene layers are embedded in a silicon-on-insulator (SOI) waveguide, the
total metal-graphene contact resistance of this structure is reduced 50% by
the graphene layers co-electrode design. By optimizing the position of each
graphene-on-graphene (GOG) layer in the waveguide, a strong interaction
between graphene layers and light is obtained, which leads to a significant
change of the effective mode index (EMI) in the waveguide. Calculations
show that an electro-absorption optical modulator can achieve 34 dB
extinction ratio (ER) and 100 GHz modulation bandwidth with 5 µm-long
active region and 17.6 fJ/bit consumption.
©2014 Optical Society of America
OCIS codes: (130.3120) Integrated optics devices; (230.4110) Modulators; (310.6845) Thin film
devices and applications.
References and links
1. R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim,
“Fine structure constant defines visual transparency of graphene,” Science 320(5881), 1308 (2008).
2. F. Wang, Y. B. Zhang, C. S. Tian, C. Girit, A. Zettl, M. Crommie, and Y. R. Shen, “Gate-variable optical
transitions in graphene,” Science 320(5873), 206–209 (2008).
3. J J. T. Kim, Y. J. Yu, H. Choi, and C. G. Choi, “Graphene-based plasmonic photodetector for photonic integrated
circuits,” Opt. Express 22(1), 2460–2465 (2012).
4. P. L. Huang, S. C. Lin, C. Y. Yeh, H. H. Kuo, S. H. Huang, G. R. Lin, L. J. Li, C. Y. Su, and W. H. Cheng, “Stable
mode-locked fiber laser based on CVD fabricated graphene saturable absorber,” Opt. Express 20(3), 2460–2465
(2012).
5. J. Gosciniak and D. T. H. Tan, “Graphene-based waveguide integrated dielectric-loaded plasmonic
electro-absorption modulators,” Nanotechnology 24(18), 185202 (2013).
6. C. Xu, Y. C. Jin, L. Z. Yang, J. Y. Yang, and X. Q. Jiang, “Characteristics of electro-refractive modulating based
on Graphene-Oxide-Silicon waveguide,” Opt. Express 20(20), 22398–22405 (2012).
7. C. C. Lee, S. Suzuki, W. Xie, and T. R. Schibli, “Broadband graphene electro-optic modulators with
sub-wavelength thickness,” Opt. Express 20(5), 5264–5269 (2012).
8. R. Hao, W. Du, H. S. Chen, X. F. Jin, L. Z. Yang, and E. P. Li, “Ultra-compact optical modulator by graphene
induced electro-refraction effect,” Appl. Phys. Lett. 103(6), 061116 (2013).
9. M. Liu, X. B. Yin, E. Ulin-Avila, B. S. Geng, T. Zentgraf, L. Ju, F. Wang, and X. Zhang, “A graphene-based
broadband optical modulator,” Nature 474(7349), 64–67 (2011).
10. M. Liu, X. B. Yin, and X. Zhang, “Double-layer graphene optical modulator,” Nano Lett. 12(3), 1482–1485
(2012).
11. H. Li, Y. Anugrah, S. J. Koester, and M. Li, “Optical absorption in graphene integrated on silicon waveguides,”
Appl. Phys. Lett. 101(11), 111110 (2012).
12. J. M. Dawlaty, S. Shivaraman, J. Strait, P. George, M. Chandrashekhar, F. Rana, M. G. Spencer, D. Veksler, and Y.
Chen, “Measurement of the optical absorption spectra of epitaxial graphene from terahertz to visible,” Appl. Phys.
Lett. 93(13), 131905 (2008).
13. S. J. Koester and M. Li, “High-speed waveguide-coupled graphene-on-graphene optical modulators,” Appl. Phys.
Lett. 100(17), 171107 (2012).
14. J. T. Smith, A. D. Franklin, D. B. Farmer, and C. D. Dimitrakopoulos, “Reducing contact resistance in graphene
devices through contact area patterning,” ACS Nano 7(4), 3661–3667 (2013).
15. F. Xia, V. Perebeinos, Y. M. Lin, Y. Wu, and P. Avouris, “The origins and limits of metal-graphene junction
resistance,” Nat. Nanotechnol. 6(3), 179–184 (2011).
Received 20 Aug 2014; revised 4 Oct 2014; accepted 5 Oct 2014; published 16 Oct 2014
20 October 2014 | Vol. 22, No. 21 | DOI:10.1364/OE.22.026173 | OPTICS EXPRESS 26173