• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.43-49
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• 2000

In this paper, a novel wavelength selectable multi-channel OADM(Optical Add/Drop Multiplexers) is proposed and experimentally demonstrated. The proposed OADM drops simultaneously more than one channel among many channels with small wavelength tuning by using one sampled grating and FBGs, Interchannel crosstalk (or interchannel rejection ratio) better than 20[dB] has been shown experimentally.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.235-238
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• 2008

In this paper, we have developed wavelength swept laser system for the swept source optical coherence tomography(SS-OCT). A laser is constructed by using the two SOAs parallel configuration, fiber Fabry-Perot tunable filter(FFP-TF). The wavelength sweeps are repetitively generated with the repetition period of 50Hz. The wavelength tuning range of the laser is more than FWHM of 80nm centered at the wavelength of 1310nm and the line-width of the source is 0.12 nm.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.306-307
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• 2003

기존의 WDM용 실리콘 파브리-페로 파장 가변 필터의 경우는 E-beam 박막 증착이나 CVD 박막 증착법을 사용하여 두께 제어가 잘 이루어지지 않았고, 제작된 실리콘 파브리-페로 필터의 굴절율을 변화시키기 위한 패턴이 고가의 백금(Pt)으로 이루어졌다. 이에 수 nm로 박막 두께를 제어해보고, 고가의 백금이 아닌 저가의 물질을 이용하여 온도제어를 이루어 보고자 하였다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.192-193
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• 2002

지금까지 측면이 코어 가까이 연마된 잔일모드 광섬유와 평면 도파로 사이의 광결합을 이용한 소자들이 많이 연구되고 있다. 이를 이용한 소자들로는 광필터, 광변조기, 광스위치, 굴절계, 편광기 등이 있으며 최근에는 파장분할다중화(WDM)에서 인접채널간의 채널분리를 위한 소자로서 빗살필터의 연구 또한 활발히 이루어지고 있다. 이에 본 논문에서는 측면이 코어 가까이 연마된 단일모드 광섬유와 평면도파로 사이의 광결합을 이용한 빗살필터를 제작하였으며 열광학 효과를 이용하여 파장 가변 빗살 필터를 구현해 보았다. (중략)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.656-661
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• 2002

Multipass Ti:sapphire amplifier for the light source of lidar was developed in an angular-multiplexing, and the characteristics of output energy and spectrum was investigated. In the two-stage multipass amplifier, we obtained the maximum output energy of 42 mJ, the amplification gain of 21 dB and the output efficiency of 26% on the wavelength of 790 nm. In the tuning range of 715~930nm the spectral linewidth is 0.05 $cm^{-1}$ /. The conversion efficiencies of 35% for SHG at 780 m and 13% for THG at 390 nm are obtained respectively. The continuous tunabilities of 240~306 m UV region and 360~460 nm in deep-blue region could be achieved.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.674-679
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• 2003

We fabricated erbium-doped fiber ring laser with a new structure that can operate in C- & L-band wavelength region. The wave-length of the laser can be tuned continuously over 102 nm between 1510.4-1612.6 nm by insertion of the fiber Fabry-Perot tunable filter (FFP-TF) in the ring cavity. By use of the wavelength tunable characteristics of our fiber laser, we measured absorption spectra of more than fifty transition lines of the acetylene ($^{13}$ C$_2$H$_2$) molecule with high signal to noise ratio (SNR).

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.321-326
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• 2003

We constructed grating- tuned external cavity semiconductor lasers using Littman and Littrow configuration, for which the wavelengths are tuned by rotation of the grating. This wavelength tunable semiconductor laser is one of the main devices of WDM optical communication. In Littman configuration, the wavelength range of about 60 nm (The C- and L-band range of 1,530~1,590 nm) was obtained by changing the incidence angle of the grating about $\pm$1$^{\circ}$ from the incidence angle of 70$^{\circ}$. In the 40 nm tuning range, the output power variation was less than 1.25 ㏈ and the side mode suppression ratio(SMSR) was 32 ㏈. In Littrow configuration (The incidence angle and the first order diffraction angle is the same, i.e. $\alpha$=$\delta$), the wavelength tuning range was about 80 nm for the same conditions used in Littman configuration except the incidence angle ($\alpha$=49$^{\circ}$). In 60 nm tuning range, the output power variation was less than 1.5 ㏈ and SMSR was 35 ㏈.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.166-167
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• 1998

• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.16-20
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• 1995

We have studied the spectral narrowing characteristics of the tunable Ti:sapphire laser pumped by the second harmonic generation of Nd:YAG laser. Ti:sapphire laser has uniform excitation distribution by both-side end pumping. We have controlled the angle of grating linearly and achieved the continuous selection of wavelength in the broad range from 705 to 835 nm. The output energy of $380{\mu}J$ at 790 nm. the spectral linewidth of $0.13cm_{-1}$ and the beam divergence of 1.2 mrad have been obtained. The wavelength range with power more than 50% of maximum output was 730-825 nm.825 nm.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2303-2305
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• 2005

현재 광통신 분야는 보다 많은 정보를 동시에 전송하기 위해 다양한 다중화 방식들을 요구 받고 있다. 광섬유 Bragg 격자 소자를 이용한 모든 광 분기/결합 장치는 분기/결합할 수 있는 신호가 광섬유 격자 소자의 Bragg파장에 의해 정해지므로 하나의 광섬유 격자 소자는 고정된 한 채널만을 분기, 결합할 수 있다는 단점을 지니고 있다. 그러나 광섬유 격자에 온도와 스트레인(strain) 같은 외부 물리량을 가하게 되면 광섬유 격자의 주기가 변하게 되어 반사파장이 고정되지 않고 파장을 가변 할 수 있는 장점을 가지게 된다. 이에 본 논문에서는 광섬유 격자 소자에 가해진 온도, 스트레인에 의해 Bragg파장이 변화하는 성질을 이용하여 파장 가변형 Bragg 격자를 제작 및 실험을 통하여 전광필터 특성에 대하여 제시하였다.