• The Journal of the Acoustical Society of Korea
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• v.17 no.3
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• pp.37-46
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• 1998

본 연구에서는 압전 세라믹인 PZT를 이용하여 두께 진동모드의 다중모드 필터를 설계, 제작하였다. 다중모드 세라믹필터의 등가회로를 설계하였고, 이를 이용하여 설계변수 인 물성변수와 형상변수에 따른 필터전달특성의 경향을 분석하였다. 이를 바탕으로 10.7MHz의 중심주파수를 가지는 세라믹필터를 제작하였고, 설계변수 중에서 압전세라믹 기 판과 전극형상의 변화에 따른 필터의 전달특성의 변화를 실험적으로 검증하였다. 본 연구를 통한 경향분석결과는 다양한 진동모드와 다양한 주파수대를 가지는 다중모드 필터를 설계하 는데 있어서 유용한 도구로 사용될 수 있을 것이다.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.190-191
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• 2002

광소자 설계 시 TE/TM 분극에 대한 민감도는 매우 중요한 요소로 작용을 한다. 이러한 민감도를 줄이기 위해 많은 광소자에 다중모드 간섭기가 이용되고 있다. 다중모드 간섭기에 입력되는 신호는 TE와 TM 두 모드의 분극으로 이루어져 있으며, 각각은 도파로 내에 존재하는 모드에 실려 50：50의 파워 분배를 가지고 진행하게 된다. 그러므로 광소자를 제작하기 위해 TE 또는 TM 모드만을 고려하는 것은 소자의 효율을 떨어뜨리는 요인으로 작용한다. (중략)

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.15-19
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• 2004

We presented the holographic memory system using a multi-mode optical fiber. In this system, we multiplexed multiple holograms using the lights from multi-mode optical fibers as reference beams. The proposed system has two degrees of multiplexing freedom: speckle pattern of light coming from multi-mode fiber and spatial location of multi-mode fibers. Therefore, the data addressing in the system can be performed by mode and spatial multiplexings.

• Journal of Sensor Science and Technology
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• v.11 no.5
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• pp.273-278
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• 2002

An intrusion-sensitive capability of multimode graded-index (GRIN) optical fibers under bending has been investigated. In this system, the data light is transmitted in the fundamental mode while alarm monitor light is launched in a high-order mode at the same time. An attempted intrusion to drain data by bending the fiber results in greater attenuation of a monitor signal in higher order modes, thereby setting off an alarm at the receiver. Light propagation in a multimode graded-index fiber is also analyzed theoretically when the fundamental mode is selectively excited and the fiber is bent around a constant radius mandrel. The bending generates coupling between the various modes of the fiber. Power transitions of the fundamental mode by changing the bending radius were also analyzed numerically using program simulation. It is shown that Asawa-Taylor model[4] is valid up to 1cm of the radius of curvature of the fiber bend.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.1
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• pp.14-19
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• 2010

In this paper, a novel architecture for device miniaturization of multimode interference-based couplers (MMICs) is proposed by replacing conventionally designed MMICs by cascaded two-section stepped-width or stepped-index MMICs. For the 82% cross coupling efficiency in a stepped-width MMIC, the coupling length of device results in just 6.7% length reduction. However, for a stepped-width and stepped-index MMIC, the coupling efficiency increases to 93% and the length reduction of 9% occurs. Furthermore, with additional incorporation of tapered devices, it shows that a compact MMIC can be designed in which the coupling efficiency is 90% and the length is reduced to 25%.

• Korean Journal of Optics and Photonics
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• v.20 no.1
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• pp.41-47
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• 2009

We report the spectral characteristics of Multimode Interferometer (MMI)-coupled semicondoctor square ring resonators. The epitaxial layers of the proposed semiconductor ring resonator consists of $1.55{\mu}m$ GaInAsP-InP multiple quantum wells. The lasing characteristics were observed by varying the structure parameters of the MMI-coupled square ring resonators. It is concluded that the MMI-coupled scheme selects a single spectral lasing mode in the double square ring cavities.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.47-52
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• 2011

In this paper, to evaluate the design properties of 3D optical multimode interference (MMI) couplers with ultracompact width, modal transmission line theory and effective dielectric method are combined with together. A coupling efficiency based on the composed approach is defined, and the coupling length is numerically determined for the design of 3 dB coupler, cross coupler and bar coupler. The simulation result shows that the designed MMI coupler has a low insertion loss and a high splitting ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.6
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• pp.296-307
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• 1985

The reults of the interlaboratory measurement comparison of the multimode and single mode fiber papameters are reported. 7 multi-mode fiber spools and 4 single mode spools are used and 5 independent domestic organizations (ETRI & 4 optical fiber manufacturing companies) are participated in the comparison study. Our results are compared with those of the comparison studies conducted in the foreign countries.

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.38-43
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• 2002

Simple principles of self-imaging in Multi-Mode Interference (MMI) devices are based on the approximation of propagation constants. The analysis of the basic nature of the self-imaging principle reveals the problems of previous optimization methods, and provides a new scheme to optimize the external variables for the reconciliation of approximation problems by considering two different tendencies of approximation effects. Furthermore, the representative mode method is proposed to make the application easy. This optimization method provides an essential method for stable design and fabrication of MMI devices with improved characteristics.

• Korean Journal of Optics and Photonics
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• v.9 no.1
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• pp.25-30
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• 1998

In this paper, a simple scheme of optical interconnections between M input and N output terminals using mode speckle patterns generated in the mulitmode optical fiber is described. It is shown that fully parallel nonblocking interconnections are accomplished by using properly generated mode speckle patterns as destination codes and dectecting the generated mode speckle patterns separately using M multiplexed Vander Lugt matched filters at each output terminal. The orthogonality condition of mode speckle patterns is investigated by either changing the launching angles or rotating the polarization direction of the beam. Preliminary experiments by use of a 4$\times$4 graded refractive-index multimode fiber coupler whose core diameter was 50 ${\mu}{\textrm}{m}$ were performed to show the feasibility of our scheme.