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최춘기,황건,Choi, C.G.,Hwang, G. 한국전자통신연구원 2000 전자통신동향분석 Vol.15 No.4
본 논문은 현재 교환시스템의 시스템 랙(rack)간 전송에 사용되는 전기적 신호전송 매체의 한계인 155Mbps 또는 250Mbps에서 15m의 전송거리라는 제약을 극복하고 또한 기존의 단순 동기식 전송방식(1:1)에서 탈피하여 다중/역다중 접속방식(16:1)을 채택하여 고밀도, 저가격, 다중화/역다중화 기능을 포함하는 광송수신 모듈을 개발한 내용을 기술하고 있다. 본 기술은 155Mbps 16채널의 전기적 신호를 2.5Gbps 광신호로 변환하여 양방향으로 전송할 수 있는 Twin-ax/Optical Bus Access Module 개발에 관한 것이다.
고분자 광도파로용 핫엠보싱 마스터의 표면거칠기 최소화를 위한 열산화 영향
최춘기,정명영 한국진공학회 2004 Applied Science and Convergence Technology Vol.13 No.1
핫엠보싱 기술을 이용하여 고분자 광도파로를 제작하기 위해서는 핫엠보싱 마스터가 필수적이며, 본 연구에서는 deep-RIE 공정에 의해 실리콘 마스터를 제작하였다. 광도파로의 광손실과 직접 연관이 있는 실리콘 마스터의 측면 거칠기를 최소화하기 위해 deep-RIE 공정 수행 후, 온도 $1050^{\circ}C$에서 $H_2/O_2$ 분위기하에 산화층을 각각 400$\AA$, 1000$\AA$, 3000$\AA$, 4500$\AA$, 5600$\AA$ 및 6200$\AA$ 두께로 형성하였으며, 곧바로 $NH_4$F:HF=6:1 BOE를 사용하여 산화층을 제거하였다. 제작된 마스터의 측면 거칠기를 SPM-AFM을 이용하여 측정하였으며, 측면 거칠기가 scallop 부분의 경우, 산화층 형성과 제거 후, 12nm (RMS)에서 최소 약 6nm (RMS)로 개선되었으며, vertical striation부분은 162nm (RMS)에서 최소 39m (RMS)로 개선됨을 확인하였다. Hot embossing master is indispensable for the fabrication of polymeric optical waveguides using hot embossing technology. Sidewall roughness of silicon master is directly related to optical loss of optical waveguides In this paper, a silicon master was fabricated by using a deep-RIE process. Additionally, thermal oxidation followed by oxide removal was carried out to minimize etched Si sidewall roughness. Thermal oxidation and oxide removal were performed with $H_2O_2$ atmosphere at $1050^{\circ}C$ and $NH_4$F:HF=6:l BOE, respectively, for the oxide thickness of 400$\AA$, 1000$\AA$, 3000$\AA$, 4500$\AA$, 5600$\AA$ and 6200$\AA$. The sidewall roughness was characterized by SEM and SPM-AFH measurements. We found that the roughness was improved from 12nm (RMS) to 6nm (RMS) for the scalloped sidewall and from 162nm (RMS) to 39nm (RMS) for the vertical striation sidewall, respectively.
Photonic-Crystal-Type Infrared Filters for Gas Sensors
최춘기,오상순 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.3
For the purpose of carbon-dioxide (CO2) sensors,we propose a photonic crystal (PhC)-type filter that has a narow pas band at a wavelength of 4.26 μm in the infrared region. Using the nite- difference time-domain (FDTD) method, we obtained the transmision spectra for various shapes and sizes of the air holes in the PhC type filters. On the basis of the numerical results, we designed and fabricated a PhC-type filter. By measuring the transmision spectra of the fabricated devices, we confirmed that the PhC-type filter could be a candidate for an element of an optical gas sensor. The behavior of the spectral response of the filter with respect to the shape and the size of the air holes was also analyzed.
Hot Embossing기술을 이용한 병렬 광접속용 고분자 광도파로 제작
최춘기,김병철,한상필,안승호,정명영 한국광학회 2002 한국광학회지 Vol.13 No.3
병렬 광접속용 다중모드 고분자 광도파로를 제작하였으며, 도파로 구조는 LIGA 공정에 의해 제작된 니켈 성형 마스터에 의해 hot embossing기술을 이용하여 성형하였다. 도파로 크기가 48$\times$47$\mu\textrm{m}$$^{2}$인 다중모드 광도파로를 단순 2단계 공정에 의해 제작하였으며, 0.85$\mu\textrm{m}$과 1.3$\mu\textrm{m}$ 파장대역에서 측정한 다중모드 광도파로의 도파손실은 각각 0.38dB/cm와 0.66dB/cm이었다. Polymeric multi-mode optical waveguides were fabricated for parallel optical interconnection. Waveguide structures were molded by a Ni mold master using a hot embossing technique. The Ni mold master was manufactured by LIGA process. Multimode optical waveguides with a 48$\times$47 ${\mu}{\textrm}{m}$$^2$cross-section were produced by a simple two-step process. The propagation losses of the multimode waveguide measured at 0.85 ${\mu}{\textrm}{m}$ and 1.3 ${\mu}{\textrm}{m}$ wavelengths were 0.38 dB/cm and 0.66 dB/cm, respectively.
화염 가수분해 증착에 의해 형성된 $SiO_2-P_2O_5-B_2O_3$ 유리 미립자의 특성
최춘기,정명영,최태구 한국세라믹학회 1997 한국세라믹학회지 Vol.34 No.8
SiO2-P2O5-B2O3 glass soot was fabricated by flame hydrolysis deposition and their properties by SEM, XRD, TGA-DSC were investigated., The mechanism of consolidation process of a glass soot as a function of consolidation temperature was analyzed by SEM observations. In the XRD patterns, the crystalline peaks which seem to be generated from B2O3 and BPO4 were observed. When the temperature of heat treatment exceeded 105$0^{\circ}C$, the non-crystalline state of SiO2-P2O5-B2O3 glass was observed. In the TGA-DSC curves, the evaporation of water molecule by a sudden endothermic reaction was observed at 128$^{\circ}C$ and a broad endothermic peak was seen in the temperature range of 40$0^{\circ}C$-95$0^{\circ}C$, without any weight loss. Finally, this peak was began to recover its baseline at 953$^{\circ}C$. This point is equal to the temperature at which the densification begins. Furthermore, we observed that the addition of dopants such as P2O5 and B2O3 decrease the onset of consolidation temperature till 95$0^{\circ}C$.
레이저 표면용융에 의한 Al-12% Si 합금의 미세조직 형성
최춘기 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.12
The surface of Al-Si 12% alloys has been modified by laser surface melting process. A 5 kW CO₂ laser has been used to melt the surface of casting alloy. The dimension and microhardness of molten zone have been investigated for mono- and multi-pass. The dimension of molten zone depends on the parameters (power, scanning velocity......) of laser beam. The microhardness increases as the crystalline size and interdendritic space decrease and the scanning velocity increases. A substantial reduction of silicon particle size has been achieved from about 50 microns before laser melting to about 1 micron after laser melting with scanning velocity of 1 m/min. The relationship between solidification rate and scanning velocity has been also studied. The solidification rate begins to zero at the interface between substrate and molten zone, and rapidly increases up to a value equivalent to the scanning velocity at the surface. Interdendritic space depends on the quenching rate. It decreases with the speed of treatment and it is about 1 micron with a scanning velocity of 10 m/min.