A mode solver based on the spectral element method with mesh adaptation is proposed to calculate the modal characteristics of a semivectorial field in open varying-index optical waveguides. General optical waveguides ...
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A mode solver based on the spectral element method with mesh adaptation is proposed to calculate the modal characteristics of a semivectorial field in open varying-index optical waveguides. General optical waveguides with varying refractive indices are studied for the transverse electric and transverse magnetic cases, where perfectly matched layers (PMLs) are used to truncate the unbounded waveguides. The optical field expanded by a suitable set of orthogonal basis points (Gauss-Lobatto-Legendre or Gauss-Chebyshev collocation points) through the spectral element method are all represented by processing of characterization of composite material through mesh adaptation. By this combined solver, a large number of accurate PML modes can be easily calculated. Our results are still found to be in good agreement with those produced by other numerical methods, but with more efficiency. Additionally, the relations of the PML modes' distribution to the parameters of PMLs are analyzed through the pitchfork phenomenon in the spectrum. (C) 2017 Optical Society of America
Optical waveguides have been fabricated via photopolymerization of stable, inkjet-printed patterns. In order to obtain high-profile lines, the properties of both the ink and the substrate were adjusted. We prove that ...
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Optical waveguides have been fabricated via photopolymerization of stable, inkjet-printed patterns. In order to obtain high-profile lines, the properties of both the ink and the substrate were adjusted. We prove that suitable patterns, *** angles close to 90 degrees, can be printed by using not fully cured, "sticky" PDMS as a substrate. In addition, we propose a simple sliding-drop experiment to show the crucial difference in how the ink dewets the "sticky" and the fully cured substrate, which is otherwise difficult to demonstrate. The light attenuation vs strain curve of the obtained waveguides was determined experimentally and was found to be almost linear within the measured strain range.
As modern complementary-metal-oxide-semiconductor (CMOS) circuitry rapidly approaches fundamental speed and bandwidth limitations, optical platforms have become promising candidates to circumvent these limits and faci...
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As modern complementary-metal-oxide-semiconductor (CMOS) circuitry rapidly approaches fundamental speed and bandwidth limitations, optical platforms have become promising candidates to circumvent these limits and facilitate massive increases in computational power. To compete with high density CMOS circuitry, optical technology within the plasmonic regime is desirable, because of the sub-diffraction limited confinement of electromagnetic energy, large optical bandwidth, and ultrafast processing capabilities. As such, nanoplasmonic waveguides act as nanoscale conduits for optical signals, thereby forming the backbone of such a platform. In recent years, significant research interest has developed to uncover the fundamental physics governing phenomena occurring within nanoplasmonic waveguides, and to implement unique optical devices. In doing so, a wide variety of material properties have been exploited. CMOS-compatible materials facilitate passive plasmonic routing devices for directing the confined radiation. Magnetic materials facilitate time-reversal symmetry breaking, aiding in the development of nonreciprocal isolators or modulators. Additionally, strong confinement and enhancement of electric fields within such waveguides require the use of materials with high nonlinear coefficients to achieve increased nonlinear optical phenomenon in a nanoscale footprint. Furthermore, this enhancement and confinement of the fields facilitate the study of strong-field effects within the solid-state environment of the waveguide. Here, we review current stateof- the-art physics and applications of nanoplasmonic waveguides pertaining to passive, magnetoplasmonic, nonlinear, and strong-field devices. Such components are essential elements in integrated optical circuitry, and each fulfill specific roles in truly developing a chip-scale plasmonic computing architecture.
Compact planar laminate-based transitions for integrating high-frequency photodiodes (PDs) with rectangular waveguides (WRs) are presented for the WR15 to WR1 standard waveguide bands, i.e., from 0.05 THz up to 1.1 TH...
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Compact planar laminate-based transitions for integrating high-frequency photodiodes (PDs) with rectangular waveguides (WRs) are presented for the WR15 to WR1 standard waveguide bands, i.e., from 0.05 THz up to 1.1 THz. The transitions couple the optically generated (e.g., via heterodyning) millimeter-wave or terahertz signals from the grounded coplanar waveguide (GCPW) output of the PD chip to the WR. To our knowledge, this is the first scalable integration concept that enables hermetic photodiode packaging up to the terahertz frequency range. For the WR15-WR6 bands, all transitions are designed on ultrathin microfiber reinforced PTFE composites (127-μm Rogers RT/duroid 5880 laminate). For the WR5-WR2.2 and the WR1.5-WR1 bands, liquid crystalline polymer ULTRALAM 3850 laminates are used with a thickness of 50 and 25 μm, respectively. The proposed GCPW-WR transition design is based on a double-slot antenna structure and enables the development of fully hermetic photonic packages, which is required to improve the durability of the PD chip. The transition designs are optimized by systematic EM-wave propagation modeling for achieving a wide operational bandwidth of up to 30% of the respective center frequency for each WR band. The optimized transitions exhibit an average insertion loss of about 1.5 dB and a return loss of about 10 dB for all waveguide bands (WR15-WR1). Based upon the systematic numerical modeling, generic guidelines are developed that allow designing a specific transition for any given waveguide band to 1.1 THz. In addition to the numerical analysis, GCPW-WR12 transitions for E-band (60–90 GHz) operation are fabricated and integrated with InP-based balanced-PD chips and GaAs HEMT MMIC medium power amplifiers in a fully hermetic package. Furthermore, hermetic WR12 coherent photonic mixer (CPX) modules are developed. The packaged WR12-type CPX allows direct optical-to-wireless conversion of optical baseband or IF-band signals, e.g., for radio-over-fiber
We present detailed Monte Carlo simulations of a simple model of a nematic liquid crystal channel waveguide investigating the effect of an applied electric external field. The simulations are based on the Lebwohl-Lash...
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We present detailed Monte Carlo simulations of a simple model of a nematic liquid crystal channel waveguide investigating the effect of an applied electric external field. The simulations are based on the Lebwohl-Lasher lattice spin model with boundary conditions chosen to mimic the homeotropic anchoring appropriate for PDMS polymer walls. The external field is modeled by adding an additional term to the Hamiltonian which describes its coupling to the mesogenic molecules. We have investigated the effect of the external field on the optical transmission and the ordering across the cell.
We present inductively-coupled-plasma, reactive-ion-etching (ICP-RIE) techniques with 2 orders of magnitude difference in etch rates, for the AlxGa1-xAs material system. These precise etching processes are used to pro...
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We present inductively-coupled-plasma, reactive-ion-etching (ICP-RIE) techniques with 2 orders of magnitude difference in etch rates, for the AlxGa1-xAs material system. These precise etching processes are used to produce waveguides in a multi-guide vertical integration (MGVI) AlxGa1-xAs chip. The MGVI AlxGa1-xAs chip vertically integrates multiple guiding layers that usually have different material properties. The fabrication of these chips requires precise and anisotropic etching. The first etching recipe used BCl3 and achieved an etch rate of 0.25 nm/s while the second one used Cl-2/N-2 gases and achieved an etch rate of more than 20 nm/s. Simple AlxGa1-xAs nanowaveguides of 800 nm width were fabricated using these recipes. We measured a propagation loss of 6.7 dB/cm at the wavelength of 850 nm. (C) 2017 Optical Society of America
We perform a numerical simulation study of hollow-core anti-resonant reflection optical waveguides (ARROWs) fabricated using lithography and material deposition in the context of their suitability as a platform for on...
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We perform a numerical simulation study of hollow-core anti-resonant reflection optical waveguides (ARROWs) fabricated using lithography and material deposition in the context of their suitability as a platform for on-chip photonic quantum information processing. We explore the effects of the core size, the number of pairs of anti-resonant layers surrounding the hollow core, and the refractive index contrast between the anti-resonant layer materials on propagation losses in the waveguide. Additionally, we investigate the feasibility of integrating these waveguides with Bragg gratings and dielectric metasurfaces to form on-chip cavities that could act as nonlinear optical elements controllable with single photons when loaded with atomic ensembles. (C) 2016 Optical Society of America
In this Letter, we present the design, simulation (2D and 3D), fabrication, and experimental characterization of compact and fully etched focusing gratings for a horizontal slot waveguide based on a silicon nitride la...
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In this Letter, we present the design, simulation (2D and 3D), fabrication, and experimental characterization of compact and fully etched focusing gratings for a horizontal slot waveguide based on a silicon nitride layer sandwiched between amorphous silicon and a silicon-on-insulator. The measured coupling losses are about 4 dB with a 3 dB bandwidth of 38 nm. The fully etched configuration allows the fabrication in a single lithography step. (C) 2017 Optical Society of America
PbS quantum dots (QDs) and channels containing QDs were fabricated by irradiation with a continuous-wave (cw) laser at lambda = 532 nm. Channels with diameters of 36 similar to 52 mu m were formed by scanning with the...
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PbS quantum dots (QDs) and channels containing QDs were fabricated by irradiation with a continuous-wave (cw) laser at lambda = 532 nm. Channels with diameters of 36 similar to 52 mu m were formed by scanning with the laser at 6-8 mu m.s(-1). Photoluminescence centered at lambda = 1290 nm was recorded. Precipitation of PbS QDs inside glasses increased their refractive indices by as much as similar to 0.002. These channels are expected to provide active waveguides that operate in telecommunication windows once the diameters of PbS QDs can be controlled precisely. (C) 2016 Optical Society of America
Fabrication of ZnO-HfO2 hybrid nanocrystals embedded 70 SiO2-(30-x) HfO2-xZnO (x=0, 2, 5, 7 and 10 mol%) ternary glass-ceramic planar waveguides doped with 1 mol% Eu-ions, by sol-gel process and dip-coating technique ...
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Fabrication of ZnO-HfO2 hybrid nanocrystals embedded 70 SiO2-(30-x) HfO2-xZnO (x=0, 2, 5, 7 and 10 mol%) ternary glass-ceramic planar waveguides doped with 1 mol% Eu-ions, by sol-gel process and dip-coating technique has been reported. The effect of varying ZnO concentration on the growth and structural evolution of ZnO-HfO2 hybrid nanocrystals were investigated using transmission electron microscopy and other spectro-scopic tools. Time-resolved PL measurements were performed to estimate the PL emission lifetimes of Eu2+ and Eu3+, present in two different local environments in the ternary matrix, as a function of ZnO concentration. Eu3+ ions exhibit double exponential decay profile for the D-5(0) -> F-7(2) emission, while the decay curves of Eu2+ ions are single exponential. The variations in the PL emission decay profiles are used as a probe to investigate the changes in the local environments of the rare-earth ions in the glass-ceramic waveguides.
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