• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.168-169
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• 2001

1.55 $\mu\textrm{m}$ 파장 대역에서 동작하는 파장가변 단일 주파수 레이저는 WDM 통신 시스템, 광섬유 센서, 분광학 분야에 유용하게 사용될 수 있다. 특히 어븀첨가 광섬유 레이저로 파장가변 단일 주파수 레이저를 구현하면 선폭이 가늘고, 세기 잡음이 작고, 출력 세기가 크다는 장점이 있기 때문에 많은 연구가 있어 왔다. 본 논문에서는 음향광학 대역투과 필터 (acousto-optic tunable bandpass filter, AOTBF)와 광섬유 흡수 격자를 사용하는 선형공진기 형태의 파장가변 단일 주파수 광섬유 레이저에 대해서 제안하고 구현하였다. (중략)

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.277-282
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• 2016

Effect of spectral drift in coherent fiber laser was investigated by injecting optical feedback to Fabry-Perot resonance loop. Er+3 doped fiber laser having unilateral optical feedback loop in Fabry-Perot configuration using two FBGs was fabricated. The optical feedback was found to be effective in linewidth reduction of fiber laser compared to the case without any optical feedback. The linewidth of three fiber lasers using above configuration were measured to be within 3kHz which is resolution-limited performance of self-heterodyne linewidth measurement set-up. The frequency drift measurement using Mach-Zehnder measurement set-up having 200m optical delay-line in one arm showed that the frequency drift rate of optical feedback fiber laser was measured as 300kHz/sec which was better than the case without optical feedback.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.135-139
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• 2016

I propose a vector passive harmonic mode-locked fiber laser based on topological insulator Bi2Se3 interacting with a fiber taper with a diameter of 7 μm. The particles of topological insulator are deposited uniformly onto the fiber taper with light pressure effect. By incorporating the fabricated saturable absorber into an Er-doped fiber laser cavity, stable mode-locked fiber is obtained. Due to the intense evanescent field of the fiber taper, strong confinement of light enhances the nonlinearity of the laser cavity, and passive harmonic mode-locking is performed. I observe a maximum harmonic mode-locking of 356th, corresponding to a frequency of 3.57 GHz. The pulse duration is 824 fs, and the full width at half maximum of the spectrum is about 8.2 nm. The polarization dependent loss of the saturable absorber is ~ 2.5 dB in the wavelength range of the C band. As the cavity contains no other polarization dependent device, the mode-locked laser is functioning in the vector state. The harmonic order vs pump power is investigated. To the best of our knowledge, this report is the highest frequency mode-locked fiber laser based on Bi2Se3. Experimental results indicate that the topological insulator Bi2Se3 functioning with a thin fiber taper is effective for vector harmonic mode-locking.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2207-2208
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• 1999

In this paper, we would like to study the oscillation characteristics of single mode fiber laser which is composed of a Fabry-Perot resonator, a pump source of 808nm Laser Diode, a $Er^{3+}$ doped single mode fiber with 0.5um diameter.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.46-53
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• 2002

A novel ultra-narrow linewidth single longtudinal mode DFB semiconductor laser in the extended FBG cavity is proposed. The 3㏈ linewidth of 20KHz was demonstrated by using self-heterodyne measurement set-up with a fiber delay line of 63km. And this linewidth was further compressed to less than 3KHz, which is resolution limited performance, by inserting E $r^{+3}$ doped fiber saturable absorber. This is equivalent to 3㏈ linewidth of 2$\times$10$^{-8}$ nm.

• Journal of the Optical Society of Korea
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• v.2 no.1
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• pp.9-12
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• 1998

Rational harmonic mode-locking of an Er-doped fiber ring laser has been successfully demonstrated up to the 16-th harmonic, of the RF frequency applied to the electro-optic modulator. This is the highest harmonic reported so far to our knowledge.

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.58-64
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• 2002

Using Mach-Zehnder type intensity modulator, we stabilized a 10 GHz harmonically mode-locked dispersion-compensated fiber ring laser using a feedback controlling system, and we measured its stability. The laser was stabilized for more than 16 hours by controlling the cavity length to suppress the relaxation oscillation frequency component which had caused the laser output instability. The ms timing jitter and ms amplitude noise were measured to be 260-524 fsec and 4~11.5%, respectively, and BER test measurement showed a value of 10$^{-13}$ .

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.214-215
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• 2001

최근 정보통신산업의 급격한 발달로 대용량의 멀티미디어 정보를 초고속으로 전달해야 할 필요성으로 인해 광전송시스템의 개발에서 수십 Gbps급 이상의 기술이 절실히 요구되고 있다. 특히 광통신 시스템이나 광계측 장비들과 결합이 쉽다는 잇점 때문에, 모드록킹된 광섬유 레이저에 대한 연구가 많이 진행되고 있다. 이러한 레이저의 제작에 있어서는 능동형 모드잠금 방식이 적합한데, 능동형 모드잠금 방식의 레이저는 수동형에 비해 안정되고 고반복률을 가진 펄스를 얻을 수 있으나 펄스폭은 상대적으로 길다. (중략)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.197-200
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• 2000

All-optical NOR logic device was realized by use of two pump signals with a single wavelength and a semiconductor optical amplifier(SOA). Specially, Mach-Zehnder(MZ) modulator was used for an external modulation of the pump signals. To obtain the sufficient gain saturation of the SOA, pump signals are amplified by an Er-doped fiber amplifier(EDFA) at the input of the SOA. Pump and probe signals are obtained from a DFB laser diode(${\lambda}_p$=1554 nm) and a tunable laser diode(${\lambda}_s$=1535 nm), respectively. The operation characteristics of the NOR logic device are successfully measured and demonstrated at the modulation frequency of 4.83 MHz.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.151-154
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• 2002

All-optical OR logic gate is realized by use of gain saturation and wavelength conversion in the semiconductor optical amplifiers (SOA). It is operated by the nonlinearity of the SOA gain and hence to obtain the sufficient gain saturation of the SOA, pump signals are amplified by an Er-doped fiber amplifier (EDFA) at the input of the SOA. The operation characteristics of all-optical OR logic gate are successfully measured at 2.5 Gbit/s.