• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.576-585
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• 2001

In this paper, we investigated the method of compensation for optical pulse shape distortion due to both chromatic dispersion and SPM(self phase modulation) in a single mode fiber We selected MSSI(mid-span spectral inversion) as compensation method using OPC(optical phase conjugator). We used EOP(eye-opening penalty) parameter in order to evaluate the efficiency of waveform distortion compensation. In this paper, we induced optimum pump power level in optical phase conjugator through analytic method of computer simulation. And we investigated input signal power range being able to maintain stable reception performance under the condition of optimum pump power. We verified the possibility of high performance optical transmission system realization through the inducement and application of optimum pump power, input signal power and in-line amplifier spacing, because power control is important in the compensation for optical pulse distortion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3318-3324
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• 2010

This study was to examine the effectiveness of neurofeedback training by observing the pre and post brainwave measurement results of about 16(Primary Student 6, middle school student10) student who have shown resistance stress and body stress, mental stress. The study was examined at S city M dong A hearing impairments student, from Mar. 2008 and to Feb. 2009. The methodology used in the study is the Coloring Analysis Program of the Brain Quotient Test. As the brain waves are adjusted by timeseries linear analysis, the brain function quotients can reflect the functional states of the brain. The training took place two times a week, for about 40 minutes per session. The result confirmed the differences of both resistance stress quotient and body stress, mental stress. The results of the analysis show that neurofeedback training plays positive role in changing the brain function. Therefore, the result of the study shows that there is possibility that Neuro Feedback technique might be positively affecting resistance stress of the hearing impairments student, relationship between neurofeedback training and stress among several categories.

• Korean Journal of Optics and Photonics
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• v.8 no.6
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• pp.510-515
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• 1997

Packaging takes an extremely important element of optical module cost due primarily to the added complication of alignment between semiconductor devices and optical fiber, and many efforts have been devoted on reducing the cost by eliminating the complicated optical alignment procedures in passive manner. In this study, we fabricated silicon optical benches on which the optical alignments are accomplished passively. To improve the positioning accuracy of a flip-chip bonded LD, we adopted fiducial marks and solder dams which are self-aligned with V-groove etch patterns, and a stand-off to control the height and to improve the heat dissipation of LD. Optical sub-assemblies exhibited an average efficiency of -11.75$\pm$1.75 dB(1$\sigma$) from the LD-to-single mode fiber coupling and an average sensitivity of -35.0$\pm$1.5 dBm from the fiber and photodetector coupling.