• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 하계학술발표회 논문집
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• pp.9-10
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• 2006

We report the realization of the Yb/Tm co-doped silica glass optical fiber amplifier operating at 1470 nm upon 980 nm pumping. The energy transfer coefficient from Yb to Tm was estimated using the threshold condition of the optical amplifier.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.238-239
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• 2000

The optical fibers are an interesting medium for effective tunable optical frequency conversion in the spectral range of UV, Visible, and near-IR through the nonlinear processes. A number of papers for developing the wideband and flat-gain amplifier for the WDM system applications through the combination of EDFA or thulium-doped fluoride fiber amplifier and Raman amplifier, are reported$^{(1)}$ . Even though a variety of papers related to Raman amplifications are published, the amplification with the feedback of the residual pump is not investigated yet. Accordingly, in this paper, we report the characteristics of forward Raman amplification by the simple and double-pass fiber Raman configuration through the feedback of residual pump beam. (omitted)

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.357-361
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• 2013

A regenerative Er-doped fiber amplifier system for a high-repetition-rate optical pulse train is investigated for the first time. A signal pulse train with a wavelength tuning range of 18 nm is produced by a passive mode-locked fiber laser based on a nonlinear polarization rotation technique. In order to realize the amplification, an optical delay-line is used to achieve time match between the pulses' interval and the period of pulse running through the regenerative amplifier. The 16 dB gain is obtained for an input pulse train with a launching power of -30.4 dBm, a center wavelength of 1563.4 nm and a repetition rate of 15.3 MHz. The output properties of signal pulses with different center wavelengths are also discussed. The pulse amplification is found to be different from the regenerative amplification system for CW signals.

• 한국광학회지
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• 제5권2호
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• pp.291-297
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• 1994

Erbium첨가 광섬유 증폭기에서 증폭된 자연방출광(ASE) 출력의 일부를 대역투과 파장 필터를 거쳐 입력단으로 루프 귀환시켜 광증폭기를 특정 파장에서 발진시킴으로써 신호광에 대한 증폭 이득을 일정치에 고정시켰다. 증폭 이득과 ASE 출력 스펙트럼은 광증폭기가 발진하는한 입력광 power나 펌프광 power의 변화에 대하여 무관하였으며 귀환 루프의 손실에만 의존하였다. 또한 광증폭기에 저속으로 변조된 대신호가 입사하는 경우에도 이득포화에 의한 파형 왜곡없이 증폭이 가능하였다.

• 전기전자학회논문지
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• 제13권4호
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• pp.103-109
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• 2009

본 논문에서는 마하-젠더 광 변조기와 EDFA(Erbium-Doped Fiber Amplifier)로 구성된 아날로그 광통신 링크에서 광 변조기에 인가되는 바이어스 전압의 조정을 통해 광통신 링크 출력의 랜덤 지터를 효과적으로 감소시키는 방법에 관하여 연구하였다. 광 변조기의 바이어스를 $0.5\;V_{\pi}$로부터 약 $0.089\;V_{\pi}$로 이동시켰을 때, 10 GHz RF 신호의 이득은 최대 10.65 dB가 증가하였고, 랜덤 지터는 EDFA의 입력 광 파워가 -0.11 dBm일 때 최대 46.5% 감소하였다.

• 한국광학회지
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• 제29권4호
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• pp.159-165
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• 2018

본 논문에서는 3단으로 구성된 전광섬유(all-fiber) Master Oscillator Power Amplifier (MOPA) 구조의 협대역 이터븀 첨가 편광 유지 광섬유 레이저 증폭에 대해 보고한다. 편광유지 단일모드 출력은 85%의 기울기 효율을 가지는 400 W 출력을 얻을 수 있었고, 레이저 반치폭은 2.5 GHz였다. 더불어, 이득매질 광섬유를 11 cm 지름으로 코일링하여 모드 불안정성을 완화할 수 있었다. 추가적으로 레이저 출력 증가를 위한 방법들에 대해 논하였다.

• ETRI Journal
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• 제27권4호
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• pp.411-417
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• 2005

$Pr^{3+}-doped$ selenide glass optical fiber, which guarantees single-mode propagation of above at least 1310 nm, has been successfully fabricated using a Ge-Ga-Sb-Se glass system. Thermal properties such as glass transition temperature and viscosity of the glasses have been analyzed to find optimum conditions for fiber drawing. Attenuation loss incorporating the effects of an electronic band gap transition, Rayleigh scattering, and multiphonon absorption has also been theoretically estimated for the Ge-Ga-Sb-Se fiber. A conventional double crucible technique has been applied to fabricate the selenide fiber. The background loss of the fiber was estimated to be approximately 0.64 dB/m at 1650 nm, which can be considered fairly good. When excited at approximately 1470 nm, $Pr^{3+}-doped$ selenide fiber resulted in amplified spontaneous emission and saturation behavior with increasing pump power in a U-band wavelength range of 1625 to 1675 nm.

• Journal of the Optical Society of Korea
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• 제18권2호
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• pp.118-123
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• 2014

For multi parameter optimization of Raman Fiber Amplifier (RFA), a simple genetic algorithm is presented in the scenario of a 320 channel Dense Wavelength Division Multiplexed (DWDM) system at channel spacing of 25 GHz. The large average gain (> 22 dB) is observed from optimized RFA with the optimized parameters, such as 39.6 km of Raman length with counter-propagating pumps tuned to 205.5 THz and 211.9 THz at pump powers of 234.3 mW, 677.1 mW respectively. The gain flattening filter (GFF) has also been optimized to further reduce the gain ripple across the frequency range from 190 to 197.975 THz for broadband amplification.

• 전자공학회논문지D
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• 제36D권6호
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• pp.97-101
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• 1999

하나의 광섬유 브래그 격자와 EDFA를 이용하여 온도와 스트레인을 동시에 측정할 수 있는 센서를 제안하고 구현하였다. 혼도에 따른 EDFA 의 ASE파워의 선형적 변화를 이용하여 온도를 측정하고 전체 브래그 파장변화와 그 온도효과의 차로써 스트레인을 측정하였다. 측정값은 스트레인과 온도 각각에 대해서 $18.2{\mu}{\varepsilon}$과 $0.7^{\circ}C$의 rms 오차를 가진다.

• Journal of the Optical Society of Korea
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• 제17권3호
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• pp.237-241
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• 2013

This paper presents an efficient evolutionary method to optimize the gain ripple of multi-pumps photonic crystal fiber Raman amplifier using the Fuzzy Adaptive Modified PSO (FAMPSO) algorithm. The original PSO has difficulties in premature convergence, performance and the diversity loss in optimization as well as appropriate tuning of its parameters. The feasibility and effectiveness of the proposed hybrid algorithm is demonstrated and results are compared with the PSO algorithm. It is shown that FAMPSO has a high quality solution, superior convergence characteristics and shorter computation time.