• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1850-1860
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• 1996

We present the results for the design ofantireflection (AR) coatings on facets of a multilayered structure waveguide device. The method, whose results agree very well with the reusults of the rigorous method in the case of a symmetric three layer structure deveice, is extended for the design of AR coatings on the facets of a multilayered structure waveguide device. the field profile in a multilayered structure waveguide necessary for the use of the extended method is obtained from the transfer matrix method. The virtual four layered structure method (VFLM) is proposed to reduce the time for the design ofAR coatings because the time for the design of AR coatings using the extended method increases as the number of layers increases. The optimum coating parameters and tolerance mapsfor two different six layered waveguide devices in Ref. [9] and [10] are obtained using the extendedmethod and the VFLM,and for the three different cases approximated as three layered waveguide devices to compare the results of each case. The results of the VFLM are similar to those of the extended methodcompared to those of the three layered structure waveguide. The main reason for the above results is that the field profile in the device calculated usingthe VFLM is similar to that calculated using the extended method compared to that for three layered structure wavegjide. We conclude that the extended method or VFLM should be used for the design of AR coatings on facets of a deice required for the facet reflectivity less than 10$^{-3}$ such as a semiconductor otical amplifier.

• Korean Journal of Optics and Photonics
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• v.7 no.3
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• pp.272-279
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• 1996

A simple transfer matrix algorithm to analyze the properties of 2 dimensional waveguides is introduced. We applied this algorithm to strained InGaAs/InGaAsP GINSCH MQW laser structures. We studied how optical confinement factor and effective refractive index, which are important in calculating the modal gain, depend on the structure parameters such as waveguide width, shape of GRIN, and number of quantum wells. Especially we suggested that the concept of effective waveguide width is very useful in understanding the GRINSCH waveguide.

• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.162-165
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• 2008

A novel planar lightwave circuit(PLC) triplexer using a three-waveguide interferometer(TWI) is proposed and examined using the transfer matrix and the beam propagation methods. The proposed triplexer consists of two three-waveguide couplers and three waveguides connecting the couplers. Simulation for the TWI triplexer shows the excess losses of 0.03 dB and 0.94 dB with the crosstalks of -22.3 dB and -14.5 dB in reception, respectively, for the wavelength of 1490- and 1550-nm, while showing the excess loss of 1.75 dB in transmission for the wavelength of 1310 nm. The proposed design shows compact feature as short as 11.5 mm for the refractive-index contrast of 0.45%.

• Korean Journal of Materials Research
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• v.19 no.12
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• pp.637-643
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• 2009

In this study, we analyzed the effect of silicon oxynitride matrix on the optical properties of Au nanoparticles dispersed on composite film and explored the effectiveness of the silicon in fine tuning the refractive index of the composite film for applications in optical waveguide devices. The atomic fraction of nitrogen in $SiO_xN_y$ films was controlled by varying the relative flow ratio of nitrogen gas in reactive sputtering and was evaluated optically using an effective medium theory with Bruggeman geometry consisting of a random mixture between $SiO_2$ and $Si_3N_4$. The Au nanoparticles were embedded in the $SiO_xN_y$ matrix by employing the alternating deposition technique and clearly showed an absorption peak due to the excitation of surface plasmon. With increasing nitrogen atomic fraction in the matrix, the surface plasmon resonance wavelength shifted to a longer wavelength (a red-shift) with an enhanced resonance absorption. These characteristics were interpreted using the Maxwell-Garnett effective medium theory. The formation of a guided mode in a slab waveguide consisting of 3 $\mu$m thick Au:$SiO_xN_y$ nanocomposite film was confirmed at the telecommunication wavelength of 1550 nm by prism coupler method and compared with the case of using $SiO_2$ matrix. The use of $SiO_xN_y$ matrix provides an effective way of controlling the mode confinement while maintaining or even enhancing the surface plasmon resonance properties.

• 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.

• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.397-409
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• 2022

A model is developed for the calculation of sea surface generated ambient noise in the range dependent ocean environment. The sources are located in the horizontal plane all around and their depths are at the near-surface. The receiver array is located in the range dependent ocean waveguide. One-way coupled mode method is used to model the acoustic propagation between the sources and receiver in the range dependent waveguide, and the cross spectral density matrix of noise is derived. In simulation, noise intensity, beamforming result and coherence function are calculated from the cross spectral density matrix. These results are compared with those in the range independent environment. The modeling result shows the effect of the vertical directionality and asymmetry characteristics of the horizontal plane.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.173-176
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• 2002

An efficient design method for E-plane waveguide bandpass filter has been developed. The analysis method for E-plane discontinuities with finite length is based on Generalized Scattering Matrix (GSM) method. Furthermore, the design portion is based on the filter synthesis method. Waveguide bandpass filters designed with this method have been fabricated and measured. Excellent agreements with design have been obtained

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.323-326
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• 1999

This paper describes a point matching method that is based on an expansion of the electromagnetic field in terms of a series of Bessel and modified Bessel functions multiplied by trigonometric functions. In this method, the electric and magnetic fields inside the waveguide core are matched to those outside the core at matching points on the boundary to yield matrix equations. As an example applying this method, the paper presents the results of the computation in the form of curves of the propagation constants in a semicircular optical waveguide, be formed by annealing for reduced insertion(radiation) loss when connected to optical fiber. The propagation curves are presented in a form of refractive index independent. Also, it presents relative energy distributions between inside the core and outside the core of various modes and presents field distributions.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.4
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• pp.45-52
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• 2000

We present a novel method for simple and efficient analysis of the rectangular MQW waveguide. Preferentially two-dimensional structure is transformed into one-dimensional structure by using the effective index method. Then, the characteristic matrix of the resultant planar MQW waveguide is analyzed by scanning angle method. The effective index, modal intensity, and optical confinement factor of rectangular MQW waveguide can be effectively obtained by this method. Our simulation results show excellent agreement with the accurate solutions based on the finite element method. We also introduce the approximation methods for the analysis of rectangular MQW waveguide and investigate their validity. By using perturbation approach, modal power loss of guided wave in rectangular MQW waveguide is newly investigated and compared with the conventional method using the approximation of planar MQW waveguide.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.108-114
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• 1998

This paper presents the design and fabrication of waveguide E-plane metal insert bandpass filter for milli-meter waves which is analyzed transmission characteristics by calculating the generalized scattering matrix using mode-matching method. The bandpass filter was fabricated to verify the proposed method by the WR-34 rectangular waveguide to operate in 30.085 ~ 30.885 GHz. The fabricated waveguide E-plane metal insert band- pass filter was established the fact that it is so adaptive for milli-meter waves due to the measured data closely consistent with the results of analysis using mode-matching method, that is, the maximum value of insertion loss is 0.8 dB and the return loss is below -15 dB.