• Journal of the Microelectronics and Packaging Society
• /
• v.27 no.4
• /
• pp.47-54
• /
• 2020

Integration of active and passive waveguides is an essential component of the photonic integrated circuit and its elements. Butt joint is one of the important technologies to accomplish it with significant advantages. However, it suffers from high optical loss at the butt joint junction and need of accurate process control to align both waveguides. In this study, we used beam propagation method to simulate an integrated device composed of a laser diode and spot size converter (SSC). Two SSCs with different mode properties were combined with laser waveguide and optical coupling efficiency was simulated. The SSC with larger near field mode showed lower coupling efficiency, however its far field pattern was narrower and more symmetric. Tapered passive waveguide was utilized for enhancing the coupling efficiency and tolerance of waveguide offset at the butt joint without degrading the far field pattern. With this technique, high optical coupling efficiency of 89.6% with narrow far field divergence angle of 16°×16° was obtained.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.11a
• /
• pp.129-130
• /
• 2007

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1986.10a
• /
• pp.20-22
• /
• 1986

This paper represents a graphical design technique of the symmetrical dielectric waveguids couplers. Once the phase constants are given by a approzimate model analysis, coupling lengths are easily calculated for each coupler. These method give some new insight of the codirectional couplers.

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.07a
• /
• pp.313-314
• /
• 2008

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.06a
• /
• pp.3-10
• /
• 2000

The undesired situation of development of tribology and its reason is analyzed. The problem comes from insufficient study on the concept system and method system, which can match the name, definition and nature of tribology. The existence of three axioms in tribology is discussed. They are axiom of system dependent, axiom of time dependent and axiom of coupling of behaviors of multi-discipline. A series of lemmas has been deduced from three axioms. It is expected that they can be a foundation to establish the concept system and method system.

• Journal of electromagnetic engineering and science
• /
• v.4 no.3
• /
• pp.102-106
• /
• 2004

A novel Genetic Algorithm(GA)-based method is suggested to transform a coupling matrix to another, without the procedure of Matrix Rotation. This can remove tedious work like pivoting and deciding rotation angles needed for each of the iterations. The error function for the GA is simply formed and used as part of error minimization for obtaining the solution. An 8th order dual-mode elliptic integral function response filter is taken as an example to validate the present method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.05a
• /
• pp.407-413
• /
• 2001

A modeling method for the vibration analysis of rotating composite cantilever plates is presented. Explicit mass and stiffness matrices are derived by considering the coupling effects between extensional motions and the bending motion, To confirm the accuracy of the method presented in this study, numerical results are obtained and compared to those of a commercial program. Numerical results show that the coupling effect among the three motions becomes important for the accurate estimation of natural frequencies as laminates are stacked up unsymmetrically. Also, natural frequencies loci veering, loci crossing, and mode shape variations are observed.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1988.10a
• /
• pp.36-42
• /
• 1988

In this study, a formulation of the idealized plate element based upon the idealized structural unit method(ISUM) firstly proposed by Ueda et．al is made in an attempt to analyze the geometric nonlinear behaviour up to the buckling strength of thin-walled long structures like box-column structure including the coupling effect between local and global buckling. An application to the example box-column is also performed and it is found that the present method gives reliable results with consuming very short computing times and therefore is very useful for evaluation of the buckling strength of thin-walled long structures.

• Journal of electromagnetic engineering and science
• /
• v.6 no.3
• /
• pp.155-159
• /
• 2006

An efficient method is presented to design filters without the similarity transform of their coupling coefficient matrix as circuit parameters, which is very tedious due to pivoting and deciding rotation angles needed during the iterations. The transfer function of a filter is directly used for the design and its desired form is derived by the optimized rational-function fitting technique. A 3rd order coaxial lowpass filter is taken as an example to validate the proposed method.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1997.04a
• /
• pp.3-10
• /
• 1997

Meshless particle method is a numerical technique which does not use the concept of element. This method can easily handle special engineering problems which cause difficulty in the use of finite element method, however it has a drawback that essential boundary condition is not satisfied. In this paper, several studies for satisfying essential boundary conditions and enhancing the accuracy of solutions are discussed. Particular emphasis is placed on a new numerical technique in which finite elements are used on the boundaries to satisfy the essential boundary conditions and meshless particle method is used in the interior domain. For coupling of the two methods interface elements are introduced into the zone between the subdomains using meshless particle method and finite element method. The shape functions and the approximated displacement functions of the interface element are derived with the ramp function based on the shape function of finite elements. The whole numerical procedures are formulated by Galerkin method. Several numerical examples for enhancing the accuracy of solution in the meshless particle method and a new coupling method are presented.