• Title/Summary/Keyword: Waveguide

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Analysis and Design of Surface Plasmon Waveguide

  • Kim, Min-Wook;Jung, Jae-Hoon
    • Journal of the Semiconductor & Display Technology
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    • v.8 no.3
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    • pp.7-11
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    • 2009
  • In this paper, we developed and presented a design result for optimizing the geometry of Ag circular SPP waveguide for subwavelength waveguide applications. We investigated the effect of the design parameters on the light propagation and find the optimum design for small modal size, high coupling coefficient, and low sensitivity. The results show that the globally optimal design locates optimal waveguide geometries more efficiently than individual optimal points for multivalued objective function.

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Planar Waveguide Devices for Communication and Sensing Applications

  • Okamoto, Katsunari
    • Journal of the Optical Society of Korea
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    • v.14 no.4
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    • pp.290-297
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    • 2010
  • The paper reviews progress and future prospects of two kinds of planar waveguide devices; they are (a) silica and silicon photonics multi/demultiplexers for communications and signal processing applications, and (b) a novel waveguide spectrometer based on Fourier transform spectroscopy for sensing applications.

The Field Analysis of Dielectric Waveguide Gratings (유전체 도파관 Grating의 필드 해석)

  • 鄭重成;李海善;尹相元;張益洙
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.1
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    • pp.15-19
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    • 1987
  • Bandstop characteristics of dielectric waveguide gratings are investigated using the modal approach. First, single step discontinuity of the dielectric waveguide is analyzed in terms of the mode matching method. Then by cascading those discontinuities characteristics of dielectric waveguide gratings are derived. Experimental results at X-band show good agreement with theoretical ones.

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Optical-Loss Measurement of a Silicon-Slab Waveguide

  • Tresna, Wildan Panji;Putra, Alexander William Setiawan;Maruyama, Takeo
    • Current Optics and Photonics
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    • v.4 no.6
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    • pp.551-557
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    • 2020
  • A mirror-in-slab waveguide is fabricated on a slab waveguide by using the refractive-index contrast between two materials, with the reflection performance depending on the slab waveguide's design. In this research, a slab waveguide design consisting of silicon (Si) as the core and SiO2 as the substrate was designed and developed to determine the coupling, waveguide, and mirror losses. Based on experimental results, coupling loss is dominant and is affected by the design of the slab waveguide. Furthermore, the mirror loss is affected by the design of the mirror, such as the curvature radius and the size of the mirror. TE and TM polarizations of light are used in the measurements. The experimental results show that mirror losses due to reflection by mirrors are 0.011 dB/mirror and 0.007 dB/mirror for TE and TM polarizations respectively. A simulation was performed to confirm whether the size of mirror is sufficient to reflect the input light, and to check the quality of the surfaces of fabricated mirrors.

Pitch-shifted sound synthesis using digital waveguide model (피치 변화음의 합성을 위한 도파관 모델)

  • Cho, Sang-Jin;Kang, Myeong-Su;Chong, Ui-Pil
    • Journal of the Institute of Convergence Signal Processing
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    • v.10 no.2
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    • pp.127-131
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    • 2009
  • In the digital waveguide theory, traveling waves are represented by general solution to the wave equation that is second-order linear partial differential equation. The movement of these waves can be implemented using only delay lines. An unit delay in the general digital waveguide describes a sampling time interval. However, in the space-based digital waveguide the unit delay implies the spatial sampling distance. In consideration of these differences between two models, it is known that the space-based digital waveguide model is adequate to synthesize pitch-shifted sounds such as vibrato because the propagation distance can be directly control. In this paper, the time-based digital waveguide model which also synthesizes pitch-shifted sounds is proposed and compared with space-based digital waveguide.

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A Study on the electric field distribution of design of LiNbO$_3$ optical waveguide (LiNbO$_3$ 광 도파로의 전계분포 및 설계에 관한 연구)

  • 강기성;소대화
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.288-293
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    • 2000
  • BPM simulation was used in order to fabricate the LiNbO$_3$optical waveguide with optical source of He-Ne laser(λ=0.6328[$\mu$m]). we observed electric field E$_{x}$, E$_{y}$ in the x,y-direction are simulated at the LiNbO$_3$substrate (X1 55[$\mu$m]$\times$Z1 5000[$\mu$m]), where the depth, width and buffer layer of waveguide are 0.2[$\mu$m],4[$\mu$m] and 0.02[$\mu$m] respectively. By applying these parameters of single waveguide to simulate a X-switch, we have chosen index change of 0.002, width of 3[$\mu$m] and angle of 0.4$^{\circ}$~0.6$^{\circ}$of optical waveguide and under these conditions, optical beam propagates cross-side at 0.4$^{\circ}$. When applied switching voltage of 25[V], optical beam of X-switch turns cross-side to bar-side at intersection angle 0.4$^{\circ}$, index change of 0.002, waveguide width of 3[$\mu$m], electrode gap 2[$\mu$m]. By the above results, we can obtain design conditions of theoretical analysis of an X-switch optical waveguide.e.e.

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A Study on the Characteristics of Monolithic Laser-Waveguide Coupler by BPM (BPM에 의한 Monolithic Laser-Waveguide Coupler의 특성 연구)

  • 장지호;최태일;최병하
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.1
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    • pp.100-110
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    • 1994
  • In this paper, we present a new analysis of monolithic laser-waveguide coupling structure employing the beam propagation method. Monolithic laser-waveguide coupler has both passive and active components It has too many parameters to consider for an analysis. So we present proper model of coupler by use of directional coupler. We employ the beam propagation method th analyze the proposed structure, we could employ the coupled mode theory but we thought in the case of this paper the beam propagation method is more appropriate than coupler mode theorybecause a number of variables which to consider is too many for the coupled mode theory. Also we use finite difference method to calcurate trial field which is a starting point of beam propagation analysis. Through this approach, we can consider more parameters. And we propose a new structure of monolothic laser-waveguide coupler which has taper structure between the distance in which coupling is taking place and passive waveguide. We can obtain 79% high coupling efficiency from our structure.

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A Proposal of Simplified Eigenvalue Equation for an Analysis of Dielectric Slab Waveguide

  • Choi Young-Kyu
    • Journal of Electrical Engineering and Technology
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    • v.1 no.3
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    • pp.381-386
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    • 2006
  • In dielectric waveguide analysis and synthesis, we often encounter an awkward task of solving the eigenvalue equation to find the value of propagation constant. Since the dispersion equation is an irrational equation, we cannot solve it directly. Taking advantage of approximated calculation, we attempt here to solve this irrational dispersion equation. A new type of eigenvalue equation, in which guide index is expressed as a function of frequency, has been developed. In practical optical waveguide designing and in calculating the propagation mode, this equation will be used more conveniently than the previous one. To expedite the design of the waveguide, we then solve the eigenvalue equation of a slab waveguide, which is sufficiently accurate for practical purpose.

Thermal Behavior of Arrayed-Waveguide Grating Made of Silica/Polymer Hybrid Waveguide

  • Kim, Duk-Jun;Shin, Jang-Uk;Han, Young-Tak;Park, Sang-Ho;Park, Yun-Jung;Sung, Hee-Kyung;Kim, Dong-Kun
    • ETRI Journal
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    • v.26 no.6
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    • pp.661-664
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    • 2004
  • The thermal behavior of an arrayed-waveguide grating made of a silica/polymer hybrid waveguide was examined. We experimentally confirmed that the hybrid waveguide is effective to decrease the temperature and polarization dependence of the center wavelength owing to the negative thermo-optic coefficient of the refractive index and extremely low baking temperature of the polymer cladding. However, the detachment of the polymer cladding from the silica core, which took place either during a repeated heat cycle test or during long-term storage in atmosphere, was a serious problem for practical use.

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Waveguiding Effect in Electroabsorption Modulators: Passivation Layers and Their Impact on Extinction Ratios

  • Shin, Dong-Soo
    • ETRI Journal
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    • v.27 no.1
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    • pp.95-101
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    • 2005
  • Waveguide structures of the stand-alone electroabsorption (EA) modulator and the electroabsorption modulated laser (EML) are investigated using the 3D beam propagation method. The EA waveguide structures with InP-based passivation layers show saturation in the extinction ratio (ER) due to the stray light traveling through the passivation layers. This paper demonstrates that narrower passivation layers suppress stray-light excitation in the EA waveguide, increasing the ER. A taper structure in the isolation section of the EML waveguide can reduce the mode mismatch and suppress the excitation of the stray light, increasing the ER further. Low-index-polymer passivation layers can confine the mode more tightly in the active waveguide, yielding an even higher ER.

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