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| 3. |
- Dai, Daoxin, et al.
(författare)
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Deeply etched SiO2 ridge waveguide for sharp bends
- 2006
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 24:12, s. 5019-5024
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Tidskriftsartikel (refereegranskat)abstract
- A deeply etched SiO2 ridge waveguide including the buffer, core, and cladding is presented for realizing sharp bends. The present SiO2 ridge waveguide has a strong confinement at the lateral direction, while it has a weak confinement at the vertical direction. Due to the strong confinement, a sharp bend (with a very small bending radius of about 10 mu m) is obtained for an acceptable bending loss. A detailed analysis of the loss in a bent waveguide is given by using a finite-difference method. In order to reduce the transition loss, a narrow bending section with an optimal lateral offset is used. A low leakage loss is obtained by using wide straight waveguides, and linear tapers are used to connect the wide straight section and narrow bent sections.
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| 4. |
- 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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| 5. |
- 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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| 6. |
- Dai, Daoxin, et al.
(författare)
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Theoretical Investigation for Reducing Polarization Sensitivity in Si-Nanowire-Based Arrayed-Waveguide Grating (de)Multiplexer With Polarization-Beam-Splitters and Reflectors
- 2009
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Ingår i: IEEE Journal of Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9197 .- 1558-1713. ; 45:5-6, s. 654-660
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Tidskriftsartikel (refereegranskat)abstract
- A novel design for reducing polarization sensitivity in silicon-on-insulator-based arrayed-waveguide grating (AWG) (de)multiplexer is presented. Each arrayed waveguide has two sections separated by a polarization beam splitter (PBS). These two sections have different core widths and length differences. With these PBSs, one polarization is reflected and the other one goes through. The through polarization enters the second section and is then reflected by a reflector at the end of the second section of the arrayed waveguide. The theoretical simulation shows that one can diminish greatly the polarization sensitivity of both the central channel wavelength and the channel spacing by optimizing the core width and length difference of the second section. The design procedure and formulas are given and an appropriate diffraction order is chosen to obtain a good fabrication tolerance. As an example, an ultrasmall (82.2 x 85.1 mu m(2)) AWG (de)multiplexer with eight channels and a channel spacing of 4 nm is designed to have minimized polarization sensitivity and Bragg-grating PBSs and photonic crystal reflectors are used.
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| 7. |
- Guan, Xiaowei, et al.
(författare)
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Ultracompact and broadband polarization beam splitter utilizing the evanescent coupling between a hybrid plasmonic waveguide and a silicon nanowire
- 2013
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 38:16, s. 3005-3008
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Tidskriftsartikel (refereegranskat)abstract
- An ultracompact polarization beam splitter (PBS) is proposed based on an asymmetrical directional coupler consisting of a silicon hybrid plasmonic waveguide (HPW) and a silicon nanowire. The widths of the two coupling waveguides are chosen so that the phase-matching condition is satisfied for TE polarization only while the phase mismatch is significant for TM polarization. A sharply bent silicon HPW is connected at the thru port to play the role of polarizer by utilizing its polarization-dependent loss. With the present principle, the designed PBS has a footprint as small as only similar to 1.9 mu m x 3.7 mu m, which is the shortest PBS reported until now, even when large waveguide dimensions (e. g., the waveguide widths w(1,2) = similar to 300 nm and the gap width w(gap) = similar to 200 nm) are chosen to simplify the fabrication process. The numerical simulations show that the designed PBS has a very broad band (similar to 120 nm) with an extinction ratio >12 dB and a large fabrication tolerance to allow a waveguide width variation of similar to 30 nm.
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| 8. |
- Guan, Xiaowei, et al.
(författare)
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Ultrasmall Directional Coupler and Disk-resonantor Based on Nano-scale Silicon Hybrid Plasmonic Waveguides
- 2012
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Ingår i: 2012 Asia Communications And Photonics Conference (ACP). - Washington, D.C. : OSA. - 9781467362740 ; , s. AS2H.4-
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Konferensbidrag (refereegranskat)abstract
- Nanophotonic integrated devices based on nano-scale silicon hybrid plasmonic waveguides have been demonstrated experimentally, including directional couplers and disk-resonators. The temperature-dependence of the hybrid plasmonic disk-resonators is also characterized.
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| 9. |
- He, Sailing, et al.
(författare)
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Some progress in integrated photonics
- 2005
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Ingår i: OPTOELECTRONIC DEVICES AND INTEGRATION. - : SPIE. - 0819455997 ; , s. 405-413
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Konferensbidrag (refereegranskat)abstract
- A review is presented on some progress we have made recently in planar integrated photonics including arrayed-waveguide gratings (AWGs) and etched diffraction gratings (EDGs), multimode interference (MMI) couplers/splitters, and spot-size converters. Some novel structures and design methods are summarized and presented.
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| 10. |
- Jiao, Yuqing, et al.
(författare)
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Accurate and efficient simulation for silicon-nanowire-based multimode interference couplers with a 3D finite-element mode-propagation analysis
- 2010
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Ingår i: Journal of the Optical Society of America. B, Optical physics. - : Optical Society of American (OSA). - 0740-3224 .- 1520-8540. ; 27:9, s. 1813-1818
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Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional (3D) finite-element mode-propagation analysis is presented to give an accurate and efficient simulation for silicon-nanowire- based multimode interference (MMI) couplers. For the presented numerical method, a finite-element method mode solver is used to calculate the mode profiles and the propagation constants in a multimode section. The comparison between the presented method and some other numerical methods [e.g., finite-difference time-domain (FDTD) method, beam propagation methods, etc.] is also shown. It is shown that the presented numerical method gives simulation results very close to those from the 3D FDTD (with a deviation less than 1%). Therefore, it is very convenient for the design of Si-nanowire-based MMI couplers.
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