• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.465-466
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• 2006

서로 다른 굴절률을 갖는 유전재료를 주기적으로 배열함으로써 광자금지대(PBG)를 형성시킬 수 있는 2 차원(2D)광자결정배열에 선결함(line defects)을 줌으로써 기존의 평판형광도파로(PLC)와는 다른 개념의 광자결정도파로를 제작할 수 있다. 특히, 광자결정도파로는 급격한 굽힘(bending)에도 저손실의 효과를 갖도록 할 수 있기 때문에 광집적회로에 효과적으로 적용된다. 본 연구에서는 정방형 격자구조의 2차원 광자결정에 대한 광자밴드구조를 구하고 이로부터 추출된 구조매개변수를 이용하여 광자결정도파로를 설계하고 그의 특성을 평가하였다. 특히, 광자결정도파로와 PLC형도파로 특성을 비교하였다. 설계된 광자결정 도파로를 전자빔 및 홀로그래픽 리소그라피를 이용하여 제작, 평가할 것이다.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.164-165
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• 2002

광자결정 광섬유(photonic crystal fiber)는 주기적으로 배열된 공기기둥이 광섬유의 길이 방향으로 정렬되어 일반광섬유의 크래팅의 역할을 하고 있고 코어는 이들 공기구멍의 중심부에 인위적인 결함을 만들어 광도파가 가능하게 된다 이러한 광자결정 광섬유의 광학적 특성은 넓은 영역에 걸친 단일 모드 특성, 특이한 모드분산 강한 비선형 등의 기존의 광섬유와는 다른 광특성이 보고되고 있으며 테라 헐즈 펄스 도파가 보고되는 등 그 응용 영역을 넓히고 있다. (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.498-501
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• 2005

Photonic crystals, periodic structure with a high refractive index contrast modulation, have recently become very interesting platform for manipulation of light. The existence of a photonic bandgap, a frequency range in which propagation of light is prevented in all direction, makes photonic crystal very useful in application where spatial localization of light is required for waveguide, beam splitter, and cavity. But fabrication of 3 dimensional photonic crystal is still difficult process. a concept that has recently attracted a lot of attention is a planar photonic crystal based on a dielectric membrane, suspended in the air, and perforated with 2 dimensional lattice of hole. We show that the polymer slabs suspended in air with triangular lattice of air hole can exhibit the in-plane photonic bandgap for TE-like modes. The fabrication of Si master with pillar structure using hot embossing process was investigated for 2 dimensional low-index-contrast photonic crystal waveguide.

• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.211-216
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• 2009

Much research into two-dimensional (2-D) photonic crystal (PC) structures has been conducted for realization of ultrasmall optical integrated circuits. A 2-D silicon (Si) PC slab structure with air cladding (n=1) is one of the representative structures in 2-D PCs. While air-clad Si PC slab structures have good optical characteristics, their suspension in air can lead to mechanical weakness, making integration with some optical devices difficult. In this paper, we propose improving the mechanical robustness of PC structure by developing a 2-D Si PC structure with symmetric silica cladding (n=1.44) and comparing its optical properties to that of the air-clad structure. First, we investigate the optical properties of a 2-D Si PC slab structure with air cladding by using a 3-D finite difference time domain method. We determined that a photonic bandgap of 330 nm and a non-leaky propagating bandwidth of 100 nm in the optical communication range are possible. Next, we investigate the optical properties of 2-D Si PC slab structures with silica cladding. Even though the refractive index of the silica cladding is higher than that of air, we developed a silica-clad structure with good optical properties: a photonic band gap of approximately 230 nm and a non-leaky propagating bandwidth of 90 nm, comparable to that of the air-clad PC structures.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.4 s.193
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• pp.153-158
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• 2007

Recently nano imprint lithography to fabricate photonic crystal on polymer is preferred because of its simplicity and short process time and ease of precise manufacturing. But, the technique requires the precise mold as an imprinting tool for good replication. These molds are made of the silicon, nickel and quartz. But this is not desirable due to complex fabrication process, high cost. So, we describe a simple, precise and low cost method of fabricating PDMS stamp to make the photonic crystals. In order to fabricate the PDMS mold, we make the original pattern with designed hole array by finding the optimal electron beam writing condition. And then, we have tried to fabricate PDMS mold by the replica molding with ultrasonic vibration and pressure system. We have used the cleaning process to solve the detaching problem on the interface. Using these methods, we acquired the PDMS mold for photonic crystals with characteristics of a good replication. And the accuracy of replication shows below 1% in 440nm at diameter and in 610nm at lattice constant by dimensional analysis by SEM and AFM.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.16-21
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• 2005

Photonic crystals, periodic structure with a high refractive index contrast modulation, have recently become very interesting platform for the manipulation of light. The existence of a photonic bandgap, a frequency range in which the propagation of light is prevented in all directions, makes photonic crystal very useful in application where the spatial localization of light is required, for example waveguide, beam splitter, and cavity. However, the fabrication of 3 dimensional photonic crystals is still difficult process. A concept that has recently attracted a lot of attention is a planar photonic crystal based on a dielectric membrane, suspended in the air and perforated with two dimensional lattice of hole. The fabrication of Si master with pillar structure using hot embossing process is investigated for two dimensional, low-index-contrast photonic crystal waveguide. From our research we show that the multiple stamp copy process proved to be feasible and useful.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.238-239
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• 2003

2차원 슬랩 형태의 단일 결함 레이저는 낮은 발진 문턱값과 작은 모드 부피로 인해 문턱 없는 레이저의 동작 가능성, 광자 집적 회로에서의 광원 소자 등으로 각광을 받고 있다. 광결정은 결정 구조에 따라 삼각격자와 사각격자로 나눌 수 있는데, 특히 삼각격자의 경우 사각격자에 비해 밴드갭이 보다 넓은 주파수 영역에 걸쳐 나타나므로, 공진기와 도파로서의 응용에 더 적합한 소재로 연구되고 있다. 2차원 삼각구조 단일 결함 광결정은 60$^{\circ}$회전에 대하여 대칭성을 가지므로, 군론에 따라 기본적으로 60$^{\circ}$,120$^{\circ}$,180$^{\circ}$,360$^{\circ}$의 회전 대칭성을 가지고 있는 네 종류의 모드가 존재한다. (중략)

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.270-272
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• 2003

We have investigated the coupling characteristics of localized modes of line defect i.e., guided modes, in photonic crystals. The parity of the coupled guided modes is not conserved when the distance between the line defects changes. By comparing the coupling characteristics of localized modes without the oscillatory nature such as cavity modes of metallic Fabry-Parot cavities with those of localized modes in photonic crystals, we confirmed that this parity nonconservation is attributed to the oscillatory nature of the evanescent waves of localized modes in photonic crystals.