Realization of chip-based all-optical and optoelectronic computational networks will require ultracompact Si-compatible modulators, ideally comprising dimensions, materials, and functionality similar to electronic complementary metal-oxide-semiconductor (CMOS) components. Here we demonstrate such a modulator, based on field-effect modulation of plasmon waveguide modes in a MOS geometry. Near-infrared transmission between an optical source and drain is controlled by a gate voltage that drives the MOS into accumulation. Using the gate oxide as an optical channel, electro-optic modulation is achieved in device volumes of half of a cubic wavelength with femtojoule switching energies and the potential for gigahertz modulation frequencies.

We report a method for obtaining unity-order refractive index changes in the accumulation layer of a metal-oxide-semiconductor heterostructure with conducting oxide as the active material. Under applied field, carrier concentrations at the dielectric/conducting oxide interface increase from 1 x 10(21)/cm(3) to 2.8 x 10(22)/cm(3), resulting in a local refractive index change of 1.39 at 800 nm. When this structure is modeled as a plasmonic waveguide, the change corresponds to a modal index change of 0.08 for the plasmonic mode.

We report a method for filtering white light into individual colors using metal-insulator-metal resonators. The resonators are designed to support photonic modes at visible frequencies, and dispersion relations are developed for realistic experimental configurations. Experimental results indicate that passive Ag/Si 3 N 4 /Au resonators exhibit color filtering across the entire visible spectrum. Full field electromagnetic simulations were performed on active resonators for which the resonator length was varied from 1-3 µm and the output slit depth was systematically varied throughout the thickness of the dielectric layer. These resonators are shown to filter colors based on interference between the optical modes within the dielectric layer. By careful design of the output coupling, the resonator can selectively couple to intensity maxima of different photonic modes and, as a result, preferentially select any of the primary colors. We also illustrate how refractive index modulation in metal-insulator-metal resonators can yield actively tunable color filters. Simulations using lithium niobate as the dielectric layer and the top and bottom Ag layers as electrodes, indicate that the output color can be tuned over the visible spectrum with an applied field.

Hybrid Si/III-V, Fabry-Perot evanescent lasers are demonstrated, utilizing InGaAsP as the III-V gain material for the first time to our knowledge. The lasing threshold current of 300-m-long devices was as low as 24 mA, with a maximal single facet output power of 4.2 mW at 15°C. Longer devices achieved a maximal single facet output power as high as 12.7 mW, a single facet slope efficiency of 8.4%, and a lasing threshold current density of 1 kA/cm 2 . Continuous wave laser operation was obtained up to 45°C. The threshold current density, output power, and efficiency obtained improve upon those of previously reported devices having a similar geometry. Facet images indicate that the output light is largely confined to the Si waveguide.

We report an unusual transition in the conductivity of an organic semiconductor upon doping: For low doping levels, the conductivity of N,N,NЈ,NЈ-tetra-p-tolyl-4-4Ј-biphenyldiamine dispersed polycarbonate increases with doping in a nearly linear fashion, and shows an activation energy of 0.2 eV. At high doping levels, a superlinear increase of conductivity with doping is observed, and the activation energy decreases, reaching a low of 0.12 eV. This behavior is understood in terms of broadening of the transport manifold due to enhanced disorder coming from the dopants.