• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.144-149
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• 1991

코헤런트 라만분광학 실험에 사용할 다중채널 데이터 수집과 제어장치를 제작하고 프로그램을 개발하였다. CARS 신호를 규격화하기 위해 두 레이저의 세기를 측정하기 위해 최대값 검출기를 제작하였고, 제작한 로직제어기를 프로그램으로 제어하여 측정을 동기시켰다. 또한 우라늄 음극전구의 optogalvanic 신호를 측정하여 섹소레이저의 파장을 교정할 수 있었다. 프로그램은 매뉴선택방식으로 작성하여 수정과 사용이 용이하도록 하였다. 실제로 압력이 100 Torr 인 질소의 CARS 신호를 측정하여 이 장치의 유용성을 확인하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.172-173
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• 2001

다중 광접속 방법 중 CDMA는 많은 수의 주소(개별 사용자를 위한 채널)를 제공하고 광 패킷 전송 방법에 있어서는 패킷들의 충돌을 피하기 위한 복잡한 장치를 필요로 하지 않는다는 장점을 가지고 있다. LED와 같은 Incoherent 광원을 이용하는 광 CDMA를 위한 여러 가지 광 코드와 암호화 방식이 제안되어 왔으며, 파장/시간 이차원 광 코드를 이용하는 방식은 AWG mux/demux 또는 AWG 라우터를 이용하여 광 코드가 용이하게 구현될 수 있음이 보고된 바 있다. (중략)

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.163-165
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• 2000

We propose a new structure of optical cross connect based on a WDM MUX/DEMUX pair and switchable mirrors. In experiment, we demonstrate the operation of the optical cross connect using an optical fiber loop mirror connected to a $2\times2$ optical switch as a switchable mirror.mirror.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.182-183
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• 2002

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.406-409
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• 2003

In this paper, a 4-wavelength optical transceiver system is designed and implemented by using TFF (thin film filter) type OADMs (optical add-drop multiplexers). In this new system, the wavelengths of 1510 nm and 1530 nm are used for uploa and download signals, respectively, as well as the wavelengths of 1550 nm and 1310 nm which have been utilized in a 2-wavelength optical transceiver systems. The 4-wavelength optical module show pass characteristics of -1.6 dBm, -1.7 dBm, -5.6 dBm, -5.8dBm for 1510nm, 1530 nm, 1550 nm, 1570 nm, respectively, with 1.2 dBm of input laser power. The isolation for characteristics of the optical module for all the wavelengths are less than -40dB, which is very acceptable for filed requirements.

• Korean Journal of Optics and Photonics
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• v.30 no.6
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• pp.226-229
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• 2019

We investigated an interrogation system for fiber Bragg gratings by using a 50-GHz 96-channel array waveguide grating. Linearity of the sensitivity (the wavelength shift in response to the change in strain or temperature) is achieved for a Bragg grating of sufficiently wide bandwidth. The present wavelength-monitoring system could measure the change in Bragg wavelength with a resolution of 0.01 nm, at intervals of 10 seconds. When this interrogation system was used for a linear array of 12 acrylaterecoated fiber gratings, the wavelength sensitivity changed from 0.018 nm/℃ to 0.01 nm/℃ when the operating temperature changed from -25℃ to 85℃.

• Journal of the Korean Vacuum Society
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• v.18 no.1
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• pp.37-43
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• 2009

Temperature and injection current dependence of electroluminescence(EL) spectral intensity of the $In_xGa_{1-x}N$/GaN multi-quantum wells(MQW) have been studied over a wide temperature range and as a function of injection current level. It is found that a temperature-dependent variation pattern of the EL efficiency under very low and high injection currents shows a drastic difference. This unique EL efficiency variation pattern with temperature and current can be explained field effects due to the driving forward bias in presence of internal(piezo and spontaneous polarization) fields. Increase of the indium content in $In_xGa_{1-x}N$/GaN multiple quantum wells gives rise to a redshift of 80 meV and 22 meV for green and blue MQW, respectively. It can be explained by carrier localization by potential fluctuation of multiple quantum well and MQW structures also shows a keen difference owing to the different indium content in InGaN/GaN MQW.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7B
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• pp.417-426
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• 2005

Routing and wavelength assignment problem is one of the most important issues in optical transport networks based on wavelength division multiplexing(WDM) technique. In this paper, we propose a novel approach using path conflict graphs and an algorithm for finding all edge disjoint paths. And then we compare the performance of the proposed algorithm with that of bounded greedy approach for EDP(BGAforEDP). The proposed one outperforms up to about 20$\%$ in the fixed traditional topology(NSFNET) and about 32$\%$ in random topologies over the BGA for EDP algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.821-828
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• 2012

In this paper, we report that the differences between RF power levels can be improved in wavelength division multiplexing - radio over fiber (WDM-RoF) system by using a photonic crystal fiber. In a WDM-RoF system, each WDM channel experiences different received RF power level fluctuation in remote node (RN) because of wavelength-dependent dispersion. Since each WDM channel experiences different power fluctuation, the RF power fluctuation acts as a design constraint in viewpoint of network design. We designed a photonic crystal fiber to improve the effect of wavelength- dependent dispersion on RF power fluctuation. Also, we analyzed the wavelength-dependent difference of inter-channel RF power fluctuations.

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.201-210
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• 2001

Wavelength and repetition-rate tunable optical pulse-trains for ultrafast optical time- and wavelength division multiplexing are generated from a semiconductor fiber ring laser by optical injection mode-locking. The pulse trains show the pulse with of ${\sim}10$ ps and the wavelength tuning of wider than 30 nm at various repetition-rates of 10 GHz, 20 GHz, 30 GHz and 40 GHz, respectively.