• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2835-2842
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• 2013

In this paper, service differentiation scheme using optical buffer that is reduced in size with slow-light technology in optical burst switching networks is presented. In suggested scheme, each outport has buffer to store high-class burst only in case that all its wavelengths are occupied. When all wavelengths are being used, a new arriving high-class burst goes into the buffer and waits until a burst is serviced. As soon as a burst is serviced with a wavelength, the high-class burst at buffer is allocated to the free wavelength. In case that low-class burst is arriving under the same situation, it is not stored at the buffer but discarded. An analytical model is derived to analyze the performance of the suggested scheme and compare its performance with the conventional scheme such as preemption and deflection as well as no service differentiations.

• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.70-75
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• 1995

Erbium 첨가 광섬유를 광원겸 광증폭기로 사용하는 방식으로 개회로 형태의 광섬유 gyroscope를 구성하였다. Erbium 첨가 광섬유를 거쳐 5mW 이상의 gyro 출력광 power와 7nm의 파장선폭을 얻었다. Loop 광섬유로부터 광증폭기형 광원으로의 feedback으로 인하여 회전속도에 따라 scale factor가 변화함을 관찰할 수 있었다. 그러나 변조된 gyro 출력신호광의 평균 power가 회전속도에 무관하도록 위상차의 변조진폭을 $\PHI_m=2.405 rad$으로 한 경우에 회전속도와 무관한 일정한 scale factor를 얻을 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.330-334
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• 2004

본 논문에서는 Nd:YAC 레이저의 제 2고조파에 의해 펌핑되는 고체레이저의 다중통과 증폭기의 이론적 고찰에 대하여 논하였다. 다중통과 증폭기의 입력레이저는 Ti:sapphire 레이저이며, 펌핑광원의 주입 후 입력 빔의 통과 회수에 따른 추출효율, 소신호 이득계수에 대한 변화 등을 조사하여 다중통과 증폭을 위한 최적조건을 구하였다. 또한, 실험에서 2단 다중통과 증폭기에서 790 nm의 입력 파장을 주입하였을 때, 42 mJ의 최대 출력에너지, 21 ㏈의 증폭이득, 25%의 출력효율을 얻었다.

• Korean Journal of Optics and Photonics
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• v.8 no.6
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• pp.476-481
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• 1997

Optimum operating conditions of the 0.98 $\mu\textrm{m}$-pumped broadband erbium-doped fiber sources, where the mean wavelength variation is minimized, have been experimentally investigated. The optimum conditions for the mean wavelength stabilization were found to be different between the case of the isolated source and the case of the presence of feedback. In case of feedback, the proper pump power that yields zero slope of mean wavelength variation was found to be lower than that of the isolated case, and the mean wavelength was found nearly unchanged over the wide range of pump power. Howerer, the feedback resulted in lower output power and the mean wavelength was found to be sensitive to the variation of feedback level. In the respect of mean wavelength stability, the better performance could be obtained with some feedback, provided that the feedback level is kept constant. Thus we could also enhance the mean wavelength stability by allowing appropriate constant feedback into the source.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.1
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• pp.47-57
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• 2002

In this paper, a wavelength converter for RZ data which can controls XPM in SOA by using polarization controller within optical fiber loop mirror is proposed and demonstrated. The proposed structure needs only one polarization dependent SOA for implementation compared to previous XPM ones and makes the cost down. And it provides wavelength converted signals with non-inverted and inverted pattern into outputs respectively.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.164-165
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• 2000

구멍에 의한 빛의 회절은 광학의 기본적인 문제로서, 최근 근접장 광학(Near-Field Optics)의 발전과 더불어서 파장보다 작은 구멍에서 일어나는 빛의 회절에 대한 관심이 고조되고 있다.$^{(1)(2)(3)}$ 본 연구에서는 그동안 주로 이론적으로 다루어지고 있던 파장보다 작은 금속 구멍을 통한 빛의 회절에 대해 실험결과들을 보고한다. 회절된 빛의 먼장(Far-field)과, 근접장(Near-field)을 모두 측정하기 위해서 고체각 주사기(Solid angle scanner)와 근접장 주사 광학 현미경(Near-field Scanning Optical Microscopy)이 사용되었다. 고체각 주사기(Solid angle scanner)를 사용하여 반구면 위에서의 빛의 이차원 세기 분포가 다양한 편광 상태에 따라서 측정되었고$^{(4)}$ 근접장 탐침(NSOM probe)으로 작은 금속 구멍주변을 주사함으로서 근접장이 측정되었다. 작은 구멍은 최근에 개발된 고출력 근접장 광섬유 탐침(High-power near-field fiber probe)구조를 이용하여 제작되었다.$^{(5)}$

• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.323-327
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• 1999

In this paper, the novel and simple scheme of producing full color image bye use of binary phase holograms and three lasers of red (632.8 nm), green (543.5 nm), and blue (488 nm) is presented. Three holograms are designed and fabricated separately so that different laser beams can pass through the different holograms. The diffracted beams from the holograms constitute the wanted color image at the focal plane. The theory and experimental results of the system are also presented.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.289-293
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• 2000

Diode-laser-pumped Tm:YAG laser of wavelength $2.02\mu\textrm{m}$has been manufactured and its excitation efficiency and output characteristics have been investigated. The excitation efficiency was varied from 66 to 68% with respect to the pump power, yielding pump power absorption of 87-89%. The output power was sensitively varied with the temperature of Tm:YAG rod. When the concave output coupler with a focal length of 25 mm and a transmittance of 3% was used, the maximum output power reached up to 1.2 W. The slope and optical efficiency of this Tm: YAG laser was 29% and 20% at $6^{\circ}C$, respectively.tively.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.257-262
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• 2001

A Littman type tunable external-cavity diode laser system was developed. The laser output which is the Oth-order diffracted beam from a diffraction grating in an external cavity is a single longitudinal mode. Its FWHM was measured as less than 9 MHz. With the diode driving current of 140 mA and operating temperature of $25^{\circ}C$, the coarse tuning range of 3.475 urn was measured. A fine tuning experiment in which an external mirror was rotated by a PZT driven by a sawtooth wave was performed, and its tuning range of 0.042 urn was measured. sured.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.270-273
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• 1998

We have demonstrated the wavelength tunable ultrashort pulse fiber ring laser proposed the novel method for measuring the cavity loss from relaxation oscillation frequency and the pump power. To suppress the polarization instability the laser cavity is configured with polarization maintaining fibers and to control the center wavelength a 2.4 nm bandwidth tunable wavelength filter was inserted in the cavity. The laser has 8 picosecond pulse width, 10 GHz repetition rate and 1.2 mW average power in 1530-1560 nm operation range.