• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.3
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• pp.148-154
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• 2005

Various methods for analyze optical components which are necessary before the fabrication of optical circuit component and as its applications, designing method of Wavelength Division Multiplexer(WDM) filter using arrayed-waveguide grating(AWG) is paper. In the case of analyzing uniform optical waveguide, effective index method(EIM), harmonic expansion method are used, and in the case of non-uniform optical waveguide, beam propagation method(BPM) are used. In this paper, to use arrayed-waveguide grating as WDM filter of centered wavelength of $1.55{\mu}m$ and wavelength spacing of 0.8nm, all of the parameter of AWG is calculated by the HEM and the BPM using EIM. As a result of calculation, free spectral range is 12.8nm, focal length $9336.55{\mu}m$, path difference $129.36{\mu}m$ and the number of slab waveguide 91 when the distance of core center to center on row land circle is $20{\mu}m$.

• Journal of the Optical Society of Korea
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• v.11 no.1
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• pp.1-5
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• 2007

We investigate the efficiency of an optical intensity modulator based on an electrically tunable $LiNbO_3$ reflection grating. Assuming a grating coupling coefficient and the waveguide propagation loss, waveguide length is varied to find its effect on the modulator slope efficiency and the device capacitance. With the low propagation loss of the $LiNbO_3$ waveguide, a very efficient optical intensity modulator can be achieved for a low frequency (${\sim}1GHz$) as long as the requirement for the grating coupling coefficient is satisfied.

• Electrical & Electronic Materials
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• v.10 no.7
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• pp.682-691
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• 1997

We have investigated the guided optical properties of a Ti:LiNbO$_3$optical waveguide which was fabricated by Ti-diffusion in an air atmosphere and proposed an effective polishing method of waveguide endfaces. And the results of guided optical mode and fabrication condition were obtained as follows; \circled1 propagation loss : 0.53 dB/cm \circled2 mode size : horizontal/vertical=12.5${\mu}{\textrm}{m}$ \circled3 mode mismatch : 1.7 dB \circled4 diffusion temperature : 105$0^{\circ}C$, time : 8 hours \circled5 atmosphere : air

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.6
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• pp.17-32
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• 1982

Wave propagation in gyrotropic or anisotropic medium is analyzed in terms of the eigenmodes of the medium, which are admixture of TE and TM waves. The field composition and the phase velocity of the modes are also determined. The results of the analysis are applied to thin film optical waveguide using such medium as substrate and/or film. Based on the characteristic equations for phase constants of the waveguide, the condition for TE-TM mode convection is derived, and wave propagation in the guide is represented in the form of Jones matrix, which allows a new interpretation in the conversion efficiency of the thin-film optical waveguides.

• Korean Journal of Optics and Photonics
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• v.24 no.4
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• pp.189-195
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• 2013

An F/1.2 infrared optical system that involves two aspheric BD-2 lenses and an aspheric diffractive surface was designed over $8-14{\mu}m$ with a field angle of $15.2^{\circ}$. The system may be used in uncooled cameras and is analyzed using beam synthesis propagation (BSP). The diffractive surface is modeled as a physical surface with a given thickness, and results are compared with those obtained by conventional methods, such as the exit-pupil method and a method which superposes diffraction orders.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.130-134
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• 2016

The influence of Au/Ni-based contact formed on a lightly-doped (7.3×1017cm−3, Zn-doped) InGaAsP layer for electrical compensation of surface plasmon polariton (SPP) propagation under various rapid thermal annealing (RTA) conditions has been studied. The active control of SPP propagation is realized by electrically pumping the InGaAsP multiple quantum wells (MQWs) beneath the metal planar waveguide. The metal planar film acts as the electric contact layer and SPP waveguide, simultaneously. The RTA process can lower the metal-semiconductor electric contact resistance. Nevertheless, it inevitably increases the contact interface morphological roughness, which is detrimental to SPP propagation. Based on this dilemma, in this work we focus on studying the influence of RTA conditions on electrical control of SPPs. The experimental results indicate that there is obvious degradation of electrical pumping compensation for SPP propagation loss in the devices annealed at 400℃ compared to those with no annealing treatment. With increasing annealing duration time, more significant degradation of the active performance is observed even under sufficient current injection. When the annealing temperature is set at 400℃ and the duration time approaches 60s, the SPP propagation is nearly no longer supported as the waveguide surface morphology is severely changed. It seems that eutectic mixture stemming from the RTA process significantly increases the metal film roughness and interferes with the SPP signal propagation.

• Journal of the Korean Society of Combustion
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• v.1 no.2
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• pp.21-29
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• 1996

Flame propagation characteristics of propane-air mixtures were experimentally investigated in constant-volume combustion chambers. Flame propagation process was observed as a function of mixture strength, initial mixture temperature and initial mixture pressure in quiescent mixtures. A cylindrical combustion chamber and a spherical combustion chamber contain a pair of parallel windows through which optical access into the chamber can be provided. Laser two beam deflection method was adopted to measure the local flame propagation, which gave information on the flame size and flame propagation speed. Pressure development was also measured by a piezoelectric pressure transducer to characterize combustion in quiescent mixtures. Burning velocity was calculated from flame propagation and pressure measurements. The effect of flow on flame propagation was also investigated under flowing mixture conditions. Laser two beam method was found to be feasible in measuring flame propagation of quiescent mixtures. Flame was observed to propagate faster with higher initial mixture temperature and lower initial pressure. Combustion duration was shortened in the highly turbulent flowing mixtures.

• Journal of the Optical Society of Korea
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• v.16 no.1
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• pp.70-75
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• 2012

An optimization methodology for designing a dielectric-filled plasmonic slot waveguide is presented. The genetic algorithm combined with a rigorous analysis based on the finite element method is used to optimize a nano-scaled plasmonic slot waveguide to have high mode confinement and a long propagation length, for which the objective function is defined as a figure of merit combining both propagation parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.55-56
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.41-42
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• 2006

An idea for extension of propagation range of surface plasmon-polaritons(SPP), which are guided on metal-strip waveguides, is suggested. Slight modification in refractive indices and/or separation gaps can increase two orders of magnitude in propagation distance of SPPs. Dispersion relations of extended long-range SPP modes excited on vertically coupled SPP waveguides are discussed in detail.