Ultra-low power modulators using MOS depletion in a high-Q SiO₂-clad silicon 2-D photonic crystal resonator.
ABSTRACT In modulators that rely on changing refractive index, switching energy is primarily dependent upon the volume of the active optical mode. Photonic crystal microcavities can exhibit extremely small mode volumes on the order of a single cubic wavelength with Q values above 10(6). In order to be useful for integration, however, they must be embedded in oxide, which in practice reduces Q well below 10(3), significantly increasing switching energy. In this work we show that it is possible to create a fully oxide-clad microcavity with theoretical Q on the order of 10(5). We further show that by using MOS charge depletion this microcavity can be the basis for a modulator with a switching energy as low as 1 fJ/bit.
Full-textDOI: · Available from: Sean Anderson, Jun 02, 2015
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ABSTRACT: In this paper, we quantitatively analyzed the trade-off between energy per bit for switching and modulation bandwidth of classical electro-optic modulators. A formally simple energy-bandwidth limit (Eq. 10) is derived for electro-optic modulators based on intra-cavity index modulation. To overcome this limit, we propose a dual cavity modulator device which uses a coupling modulation scheme operating at high bandwidth (> 200 GHz) not limited by cavity photon lifetime and simultaneously features an ultra-low switching energy of 0.26 aJ, representing over three orders of magnitude energy consumption reduction compared to state-of-the-art electro-optic modulators.Journal of Lightwave Technology 04/2013; 31(24). DOI:10.1109/JLT.2013.2280820 · 2.86 Impact Factor
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ABSTRACT: Electrical, optical and electro-optical simulations are presented for a waveguided, resonant, bus-coupled, p-doped Si micro-donut MOS depletion modulator operating at the 1.55 μm wavelength. To minimize the switching voltage and energy, a high-K dielectric film of HfO₂ or ZrO₂ is chosen as the gate dielectric, while a narrow ring-shaped layer of p-doped poly-silicon is selected for the gate electrode, rather than metal, to minimize plasmonic loss loading of the fundamental TE mode. In a 6-μm-diam high-Q resonator, an infrared intensity extinction ratio of 6 dB is predicted for a modulation voltage of 2 V and a switching energy of 4 fJ/bit. A speed-of-response around 1 ps is anticipated. For a modulator scaled to operate at 1.3 μm, the estimated switching energy is 2.5 fJ/bit.Optics Express 09/2011; 19(19):18122-34. DOI:10.1364/OE.19.018122 · 3.53 Impact Factor
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ABSTRACT: For use in on-chip and integrated applications, photonic crystals must not only be embedded in silica but must also be able to easily integrate with other photonic devices. Here we provide an experimental demonstration of resonance in a SiO(2)-clad two-dimensional photonic crystal microcavity that is coupled to standard Si strip waveguides. We further show that well over 90% of the resonant field is confined within the cavity's silicon layer, which is necessary if the microcavity is to be used as a high-efficiency electro-optic modulator.Optics Letters 07/2011; 36(14):2698-700. DOI:10.1364/OL.36.002698 · 3.18 Impact Factor