• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.33-33
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• 1997

• Proceedings of the Optical Society of Korea Conference
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• 1991.07a
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• pp.77-82
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• 1991

여러개의 레이저 빔을 결합하여 대표적인 방법의 장단점을 비교 분석하였다. incoherent 방법으로는 wavelength multiplexing, spatial multiplexing, polarization multiplexing을 분석하였고 coherent 방법으로는 binary phase grating과 travelng-were amplification을 고려하였다. 특히 고출력 laser diode array를 이용한 대출력 증폭기 시스템을 분석하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.194-195
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• 2001

We fabricated fiber bragg gratings using interferometric method with Phase mask. The interferometer consisted of two plane-parallel mirrors and a phase mask perpendicular to mirrors. The Gratings were written using an Argon-ion laser. The experimental setup could change Bragg wavelength given by the phase mask. (omitted)

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.375-376
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• 2008

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.307-308
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• 2008

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.417-418
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• 2006

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.573-578
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• 2000

This paper presents a noble optical access system using shared laser and LED light sources, which is based on WDM-PON technologies. This system adopts an external modulation of the shared laser sources for high-speed downstream and a direct modulation of the LED sources for low-speed upstream. To split or combine the transmission channels, AWG(Arrayed Wave-guide Grating) devices are used in the optical cable section. The proposed system is attractive for low cost implementation. The laser light sources can share the optical carriers in the downstream scheme. Also, in upstream, the LED sources can afford to make simple of the circuits for controlling light source and of standardization for ONU(Optical Network Unit). The feasibility of the proposed system is demonstrated by several experiments. Our results show that the system operates well at 2.SGbps for downstream and up to 622.08Mbps for upstream.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.104-109
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• 2021

In this paper, we experimentally demonstrate a self-seeding FP-LD (Fabry Perot Laser Diode) to verify the possibility of a new tunable light source that can be used in WDM-PON (Wavelength Division Multiplexing - Passive Optical Network) system. The conventional implementation of WDM-PON using a tunable light source has a disadvantage that the center wavelength of the AWG (Arrayed Waveguide Grating) device and the tunable light source must be precisely aligned. However, the proposed tunable light source has the advantage that the tunable wavelength is automatically aligned with the center wavelength of the AWG as well as simple structure. The implemented tunable light source had a tunable band of about 14 nm or more, and the maximum RIN (Relative Intensity Noise) of about -124 dB/Hz, which showed the possibility of modulating 10 Gb/s signal by an external modulator.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.169-179
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• 1998

Plane mirror type laser interferometers are popularly being used in many modern ultraprecision machines, as they can perform simultaneous measurements of multiple axis positions with nanometer resolution capabilities. One important issue in this application of laser interferometers is to provide a good level of alignment between the reflecting mirrors and the laser beams so that measurement errors due to undesirable coupling effects can be avoided in multiple axis measurements In this investigation, a thorough metrological analysis is given to develop an suitable mathematical model for a precision x-y stage in which the orthogonality misalignment between the reflecting mirrors significantly affects overall x-y mea-surement results. Then a noble calibration method is suggested in which two-dimensional displacement sensors of moire gratings of concentric circles are used to realize the reversal principle of orthogonality evaluation in situ. Finally, actual experimental results are discussed to verify that the suggested method can effectively calibrate the orthogonality error with an uncertainty of 0.2667 arcsec.

• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.146-151
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• 2010

A comprehensive real-time spectral phase interferometry for direct electric field reconstruction (SPIDER) apparatus for characterizing femtosecond laser pulses is demonstrated. The SPIDER provides the temporal profiles of femtosecond laser pulses, reconstructed at the speed of 3.5 Hz, with parameters of the spectral phase such as group delay dispersion and third-order dispersion. The apparatus is applied successfully to optimize the spectral dispersion of a kHz femtosecond Ti:Sapphire laser by adjusting a grating compressor in real time.