| 1. |
- Berglind, Eilert, et al.
(författare)
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On the Possibilities to Create a Negative Permittivity Metamaterial with Zero Imaginary Part of the Permittivity at a Specific Frequency-Electrical Network Theory Approach
- 2012
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Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 48:4, s. 507-511
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Tidskriftsartikel (refereegranskat)abstract
- A permittivity function suggested in the literature describing a material that exhibits negative permittivity and no loss at a specific frequency (and losses at other frequencies) is analyzed using electrical network theory. An equivalent circuit of the polarization admittance consisting of RLC components is derived. Further, a proof is given showing that if the admittance is lossless at a specific frequency, then all components with losses (resistances) in the circuit have to be short circuited or blocked or virtually disconnected at this frequency by the use of ideal lossless resonant LC circuits. However, in the literature, inductors in metamaterials are associated with inherently lossy metal nanoparticles, hence invalidating the suggested permittivity function unless a lossless inductor at optical frequencies is found or proved possible.
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| 2. |
- Berglind, Eilert, et al.
(författare)
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Plasmonic/metallic passive waveguides and waveguide components for photonic dense integrated circuits : a feasibility study based on microwave engineering
- 2010
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Ingår i: IET Optoelectronics. - : Institution of Engineering and Technology (IET). - 1751-8768. ; 4:1, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the potential for dense integration of photonic components, we analyse passive plasmonic/metallic waveguides and waveguide components at optical frequencies by using mostly microwave engineering approaches. Four figures of performance are formulated that are utilised to compare the characteristics of four different slab waveguides with zero frequency cut-off modes. Three of these are metallic based whereas the fourth one, which also serves as a reference, is dielectric based with high index-contrast. It is found that all figures of performance cannot be optimised independently; in particular there is a trade-off between the waveguide Q-value and the transversal field confinement. Microwave methods are used to design several photonic transmission line components. The small Q-value of the metallic waveguides is the main disadvantage when using materials and telecom frequencies of today. Hence plasmonic waveguides do not offer full functionality for some important integrated components, being severe for frequency-selective applications. To achieve a dense integration, it is concluded that new materials are needed that offer Q-values several orders of magnitude higher than metals.
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| 3. |
- Chacinski, Marek, et al.
(författare)
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ETDM Transmitter Module for 100-Gb/s Ethernet
- 2010
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 22:2, s. 70-72
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Tidskriftsartikel (refereegranskat)abstract
- Performance of a packaged distributed-feedback travelling-wave electroabsorption modulator module for data transmission at 100 Gb/s is presented for the first time. Clearly open eye diagrams at 80 Gb/s with an extinction ratio ( ER) of 4.9 dB and 100 Gb/s with ER 4.2 dB ( limited by measurement setup) are demonstrated together with data transmission over 100-m-long standard single-mode fiber and over dispersion-compensated 10-km fiber link.
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| 4. |
- Chacinski, Marek, et al.
(författare)
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Modulation and chirp evaluation of 100 GHz DFB-TWEAM
- 2010
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Ingår i: European Conference on Optical Communication, ECOC. - NEW YORK : IEEE.
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Konferensbidrag (refereegranskat)abstract
- The modulation and chirp performance of an InGaAsP based monolithically integrated distributed feedback (DFB) laser and travelling wave electro-absorption modulator (TWEAM) designed for 100Gb/s operation is presented. Open eye-diagrams at 100Gb/s, and error free 50Gb/s BER (limited by measurement system) were achieved. The chirp factor varied between 1.5 and 0 for absorptions between 10% and 90%.
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| 5. |
- Dai, Daoxin, et al.
(författare)
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Gain enhancement in a hybrid plasmonic nano-waveguide with a low-index or high-index gain medium
- 2011
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Ingår i: Optics Express. - 1094-4087. ; 19:14, s. 12925-12936
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Tidskriftsartikel (refereegranskat)abstract
- A theoretical investigation of a nano-scale hybrid plasmonic waveguide with a low-index as well as high-index gain medium is presented. The present hybrid plasmonic waveguide structure consists of a Si substrate, a buffer layer, a high-index dielectric rib, a low-index cladding, a low-index nano-slot, and an inverted metal rib. Due to the field enhancement in the nano-slot region, a gain enhancement is observed, i.e., the ratio partial derivative G/partial derivative g > 1, where g and G are the gains of the gain medium and the TM fundamental mode of the hybrid plasmonic waveguide, respectively. For a hybrid plasmonic waveguide with a core width of w(co) = 30nm and a slot height of h(slot) = 50nm, the intrinsic loss could be compensated when using a low-index medium with a moderate gain of 176dB/cm. When introducing the high-index gain medium for the hybrid plasmonic waveguide, a higher gain is obtained by choosing a wider core width. For the high-index gain case with h(slot) = 50nm and w(co) = 500nm, a gain of about 200dB/cm also suffices for the compensation of the intrinsic loss.
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| 6. |
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| 7. |
- Dai, Daoxin, et al.
(författare)
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Silicon hybrid plasmonic submicron-donut resonator with pure dielectric access waveguides
- 2011
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Ingår i: Optics Express. - 1094-4087. ; 19:24, s. 23671-23682
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Tidskriftsartikel (refereegranskat)abstract
- Characteristic analyses are given for a bent silicon hybrid plasmonic waveguide, which has the ability of submicron bending (e.g., R = 500nm) even when operating at the infrared wavelength range (1.2 mu m similar to 2 mu m). A silicon hybrid plasmonic submicron-donut resonator is then presented by utilizing the sharp-bending ability of the hybrid plasmonic waveguide. In order to enable long-distance optical interconnects, a pure dielectric access waveguide is introduced for the present hybrid plasmonic submicron-donut resonator by utilizing the evanescent coupling between this pure dielectric waveguide and the submicron hybrid plasmonic resonator. Since the hybrid plasmonic waveguide has a relatively low intrinsic loss, the theoretical intrinsic Q-value is up to 2000 even when the bending radius is reduced to 800nm. By using a three-dimensional finite-difference time-domain (FDTD) method, the spectral response of hybrid plasmonic submicron-donut resonators with a bending radius of 800nm is simulated. The critical coupling of the resonance at around 1423nm is achieved by choosing a 80nm-wide gap between the access waveguide and the resonator. The corresponding loaded Q-value of the submicron-donut resonator is about 220.
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| 8. |
- Holmstrom, Petter, et al.
(författare)
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Composite metal/quantum-dot nanoparticle-array waveguides with compensated loss
- 2010
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 97:7, s. 073110-
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Tidskriftsartikel (refereegranskat)abstract
- We calculate the dispersion properties of waveguides composed of near-field-coupled arrays of metal-clad quantum dots (QDs). The high optical loss incurred by operating the metal shells close to resonance is mitigated by using optical gain in the QDs. A condition for achieving loss compensated operation is given based on realistic material parameters and neglecting inhomogeneous broadening. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467845]
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| 9. |
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| 10. |
- Holmström, Petter, et al.
(författare)
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Dielectric function of quantum dots in the strong confinement regime
- 2010
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 107:6
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Tidskriftsartikel (refereegranskat)abstract
- The complex dielectric function of quantum dots (QDs) with a core-shell structure is modeled in the strong confinement regime. These results should be useful for the design of negative epsilon optical metamaterials, where the gain due to QDs could be an essential ingredient. Using the dielectric function it is also shown that conventional expressions for the gain substantially overestimate it for narrow linewidths.
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