• 센서학회지
• /
• 제22권1호
• /
• pp.84-88
• /
• 2013

In this paper, the low price signal generator with capability of frequency high-resolution and variable sync pulse has implemented. It fulfils well the requirements for SS-OCT of the frequency resolution less than 1Hz, frequency stability of ${\leq}{\pm}0.5Hz$/10 min and variable sync pulse output timing. Through its performance test applied to wavelength swept laser, 120 nm sweeping range and 10 mW average optical power were obtained. This shows that the realized sine-wave generator can replace the commercial high cost and high performance signal generators employed by current SS-OCT systems.

• Journal of the Optical Society of Korea
• /
• 제14권2호
• /
• pp.137-141
• /
• 2010

We report, for the first time to our knowledge, observation of polarization bistability from 1.55-${\mu}m$ wavelength single-mode VCSELs of a conventional cylinder-shape under control of their driving current, and demonstration of all-optical flip-flop (AOFF) operations based on the bistability with optical set and reset pulse injection at a 50 MHz switching frequency. The injection pulse energy was less than 14 fJ. The average on-off contrast ratio of the flip-flopped signals was about 7 dB. These properties of the VCSELs will be potentially useful for future high-speed all-optical signal processing applications.

• 한국전기전자재료학회논문지
• /
• 제17권1호
• /
• pp.16-20
• /
• 2004

We present the fabrication and performance of wavelength tunable butt coupled (BT) sampled-grating (SG) distributed bragg reflector (DBR) - planar buried heterostructure (PBH) laser diodes (LD). The fabricated LD showed the high optical output power due to the high coupling efficiency between active and passive components by the BT coupling methods. The series resistance and diode ideality factor of LD were measured to be 3.7 $\Omega$ and 1.35, respectively. The average threshold current was 25 ㎃. The output powers of BT-SG DBR-PBH-LD were obtained to be as high as 12.3 and 24.56 ㎽ at 100 and 200 ㎃, respectively. The maximum wavelength tuning range was about 31 nm and the side mode suppression ratio was about 37 dB.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
• /
• pp.450-451
• /
• 2008

In this paper, we have designed the Anti-Reflection (AR) coating for 850, 1310 nm(multi type) and 1310, 1550 nm(multi type) wavelength ranges on the ferrule facet of special optical connector. The reflectance of the AR coated ferrule facet is designed under 5% for 850, 1310 nm(multi type) and 1310, 1550 nm (multi type). AR thin film was deposited by ion- assisted deposition in low temperature. The average return loss of the AR coated ferrule facet is 47.1 dB.

• 센서학회지
• /
• 제24권6호
• /
• pp.398-403
• /
• 2015

In this paper, the sine-wave and trigger pulse generator with capability of frequency high-resolution and time-variable trigger edge has implemented. It fulfills well the requirements for SS-OCT with frequency resolution of 1 Hz, frequency stability of ${\leq}{\pm}0.03Hz$ and time-variable trigger edge. Through its performance test applied to the wavelength swept laser, 90 nm, sweeping range and 10mW average optical power were obtained. This showes that the realized generator can replace the commercial high cost and high performance signal generators employed by current SS-OCT systems.

• 수산해양기술연구
• /
• 제49권2호
• /
• pp.144-152
• /
• 2013

In an effort to find the optimum porous of Taewoo through the mathematical model 2 - dimensional tank water experiment among the approached to a problem related to ocean engineering, this study analyzed the porosity by dividing it into 9 cases. As the wave penetrates through the longitudinal porous of the Taewoo model, it was found that there is a wave energy loss because of the phenomenon of the separation of the porous due to the eddy. Looking into the general tendency based on the wave-height meter (probe) data, it was found that the shorter wavelength and higher frequency area, the more reflection coefficients increased, but in contrast, the longer wavelength and lower frequency area, the transmission coefficients showed the increasing trend and energy dissipation was in a similar way with reflection coefficients. In addition, it was found that the bigger the porosity was, the narrower distribution range of reflection coefficients was, and the more its average value decreased. On the other hand the transmission coefficients in direct opposition to reflection was found to show the wider range and the more gradual increase in the average value as porosity was the bigger around the average value. In contrast, energy dissipation rate was found to increase linearly as porosity increased the more around the porosity of 0.2518 but it decreased gradually around the peak point. Through the above results, it is judged that the porous of optimum in the longitudinal direction of the Taewoo model perforated plate was about 2.6cm because it was found that the porosity which produced the lowest reflection and transmission coefficient and the highest energy dissipation. As a result of comparing this to the case where there was no porosity at all, it showed the function of wave absorbing about 31.60%.

• Fibers and Polymers
• /
• 제4권1호
• /
• pp.32-37
• /
• 2003

The nonionic surfactant properties of ethoxylated azo dyes, such ai cloud point and surface tension have been investigated. The synthesized ethoxylated azo dyes could dye polyester fabric without any special pre-treatment. When the average number of ethylene oxide (EO) in the ethoxylated azo dye reached 6, its fixation could exceed $90^{\circ}C$ from the thermosol dyeing process. The average degree of condensation of ethylene glycol in the chain was interrelated with the dyeing results and did not affect on the maximum absorption wavelength (λmax) of the polyoxyethylene dye. When the average length of polyoxyethylene chain decreased, the molecular weight of dyes became smaller and the fixation of dyes was improved.

• 한국광학회지
• /
• 제16권3호
• /
• pp.196-200
• /
• 2005

[ $0.75delta\%$ ]의 평판광회로(PLC;Planar Lightwave Circuit)소자의 설계 및 제작기술을 가지고 저손실과 높은 누화율을 가진 파장 다중화 및 역다중화 소자를 개발하였다. C-band AWG(Arrayed Waveguide Grating)에서의 삽입손실은 2.503이하, 누화율은 35dB이상, 균일도는 1dB이하이며 L-band에서는 Vernier 디자인을 적용하여 ITU-T의 파장 정확도가 0.04nm이하가 되도록 제작하였다.

• 한국정보통신학회논문지
• /
• 제18권7호
• /
• pp.1757-1763
• /
• 2014

채널당 속도 10 Gb/s 인 8개의 NRZ 포맷을 가지는 파장다중화 광신호를 장거리 전송 링크에 적용시켜 720 km 를 전송하였다. 반복되는 링크구간은 80 km 단일모드광섬유, 완전 구간보상을 위한 분산보상광섬유, 어븀첨가 광섬유 증폭기들로 구성되었다. 전송 링크 구현을 위해 반복루프 실험 방법이 적용되었고 반복루프의 구조에 따른 신호 성능 차이가 조사되었다. 파장별 이득 평탄화는 고가의 평탄화 필터를 사용하지 않고 증폭기들의 이득 기울기를 서로 역으로 배치하여 구현하였다. 720 km 전송 후에 평균적인 OSNR 값은 22 dB 였고, 채널별로 OSNR 값의 최고 편차는 9.7 dB 였다. 이득 편차의 주원인은 Hole burning 효과에 의한 것임을 광스펙트럼 조사를 통해 확인했으며, 이득평탄화 필터 없이도 560 km 전송이 가능함을 확인했다.

• 한국재료학회지
• /
• 제28권11호
• /
• pp.680-684
• /
• 2018

We investigate the effect of light intensity and wavelength of a solar cell device using photoconductive atomic force microscopy(PC-AFM). A $POCl_3$ diffusion doping process is used to produce a p-n junction solar cell device based on a polySi wafer, and the electrical properties of prepared solar cells are measured using a solar cell simulator system. The measured open circuit voltage($V_{oc}$) is 0.59 V and the short circuit current($I_{sc}$) is 48.5 mA. Moreover, the values of the fill factors and efficiencies of the devices are 0.7 and approximately 13.6 %, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, is used for direct measurements of photoelectric characteristics in limited areas instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics are observed. Results obtained through PC-AFM are compared with the electric/optical characteristics data obtained through a solar simulator. The voltage($V_{PC-AFM}$) at which the current is 0 A in the I-V characteristic curves increases sharply up to $18W/m^2$, peaking and slowly falling as light intensity increases. Here, $V_{PC-AFM}$ at $18W/m^2$ is 0.29 V, which corresponds to 59 % of the average $V_{oc}$ value, as measured with the solar simulator. Furthermore, while the light wavelength increases from 300 nm to 1,100 nm, the external quantum efficiency(EQE) and results from PC-AFM show similar trends at the macro scale but reveal different results in several sections, indicating the need for detailed analysis and improvement in the future.