• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.318-319
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.234-235
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• 2001

최근의 극초단 펄스의 개발의 대부분은 주로 고체 이득매질을 이용하여 근적외선 영역에서 이루어지고 있다 그러나 가시광선인 500～700 nm 파장대역에서는 특성이 좋은 고체 이득매질의 개발이 이루어지지 않아, 가시광선 영역의 극초단 펄스의 개발에 대한 연구는 최근에는 거의 이루어지지 않고 있다. 현재로서 가능한 방법은 티타늄 사파이어 레이저를 이용하여 극초단 펄스를 발생시키고, 이를 CPA(Chirped Pulse Amplification)방법으로 증폭한 다음에 이의 제2고조파 펄스를 얻고, 이를 다시 광파라메트릭 방법으로 가시광선 파장영역의 극초단 펄스를 얻는 방법이 있는데, 이는 대규모의 설비 및 장치를 필요로 한다. (중략)

• Journal of the Optical Society of Korea
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• v.7 no.2
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• pp.67-71
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• 2003

For a more detailed understanding of the mechanism of an L-band erbium-doped fiber amplifier, we investigated 980 nm absorption, signal amplification and forward and backward amplified spontaneous emission along the erbium-doped fiber. In addition, we compared performances of the erbium-doped fiber amplifier with and without a fiber Bragg grating.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.294-295
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• 2002

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.293-294
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• 2008

Using bi-direction SOA based Extension system, FTTH can enhance PON system by increasing both the upstream and downstream link budget. This increased link budget can be used to extend the distance, increase the split ratio or both. The bi-direction SOA regenerates signals using all-optical amplification, and is therefore transparent to data rate or protocol. The bi-direction SOA supports legacy as well as future FTTx standards. This is based on SOA's proprietary technology platform for the manufacturing of advanced discrete photonics and photonic integrated circuits (PICs). Because the bi-direction SOA uses the same InP semiconductor technology used in virtually all telecom lasers, it is able to amplify signals at 1310 and 1490 nm, wavelengths not accessible with commercial fiber-amplifier (EDFA) technology. Due to the extremely fast response time of the InP semiconductor optical amplifiers inside, the SOA can accommodate both continuous (downstream) and bursty (upstream) traffic.

• Polymer Science and Technology
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• v.18 no.2
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• pp.142-152
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• 2007

• Journal of the Korean Society for Precision Engineering
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• v.26 no.2
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• pp.35-44
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• 2009

Long stroke Fast Tool Servo (LFTS) with maximum stroke of $432{\mu}m$ is designed, manufactured and tested for fabrication of optical free-form surfaces. The large amount of stroke in LFTS has been realized by utilizing the hinge and lever mechanisms which enable the displacement amplification ratio of 4.3. In this mechanism the peculiar shape was devised for maximizing the displacement of end tip in LFTS and special mechanical spring has been mounted to provide the sufficient preload to the piezoelectric actuator. Also, its longitudinal motion of tool tip can be measured by capacitive type displacement sensor and closed-loop controlled to overcome the nonlinear hysteresis. In order to verify the static and dynamic characteristics of designed LFTS, several features including step response, frequency response and cut-off frequency in closed-loop mode were experimentally examined. Also, basic machining result shows that the proposed LFTS is capable of generating the optical free-form surface as an additional axis in diamond turning machine.

• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.26-32
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• 1995

A Kerr cell was utilized as an optical shutter to generate a shortened pulse and as an isolator between amplifiers in an iodine laser system. By rotating the polarization of incident laser pulse only during the timing window of high voltage applied to the Kerr cell, shortened pulses of 5 ns and 1 ns, corresponding to the difference in propagation time of two coaxial cables, were obtained. It was also noticed that more than one timing window of Kerr cell was produced with a long incident laser pulse from the oscillator. The measured transmittance of Kerr cell with respect to applied voltage was compared with the theoretical estimation using the electro-optic Kerr effect theory. Through the amplification of the shortened pulse in iodine amplifiers. a pulse of 0.5 GW(2 J in 4 ns) was obtained. ained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1191-1202
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• 1994

We numerically investigate a stable propagation regime of soliton pulse trains in fibers with periodically copensated loss by lumped optical amplifiers. When amplification solition pulses is 1.2~1.5 and the minimum soliton separation normalized by the soliton width becomes about 6. In cases of L=50[km], the allowable range of A is 1.5~1.7 under =6. The maximum allowable variation of the loss compensation in each lumped amplifier becomes +-2% of the fiber loss when L=50[km], A=1.6, and =6. Generally, the allowable rages of the soliton amplitude A and amplifier gain are inversely proportional to the amplification period L.

• Proceedings of the Optical Society of Korea Conference
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• 1995.06a
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• pp.185-189
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• 1995

A high-power Nb:glass laser system(Simmyung I) has been contructed and tested. In this system, we used a Nb:YLF laser as a master oscillator, a 4-pass amplifier for pre-amplification, 5 stages of rod amplifiers, and spatial filtering and image reaying usits. The system has demonstrated in excess of 80J(2TW) with 40 psec(FWHM) pulse duration. Output energy, gain and spatial were measured at each amplification stage. With this laser system a preliminary X-ray generation experiment was performed. Pinhole images, X-ray diode signals and X-ray speriment were obtained for the irradiated target of copper. Detailed descriptions of the system performance and the X-tay generation experiment are presented.