• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.524-531
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• 1997

A novel optical cell compressor for optical time division multiplexing system is presented. The compressor is capable of generating optically compressed very high bit-rate (possibly several tens of Gb/s) signals with minimum hardware. Contrast to the previously reported optical compressor, the compressor is mainly composed of passive optical devices and requires no synchronization among control signals in the process of compression, which results in simple implementation. We demonstrate a generation of optically compressed 6 Gb/s optical cells to confirm the fundamental operation of the compressor.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.215-218
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• 2002

In this paper some of optical current transformers and optical potential transformers for extra high voltage system are introduced. The optical current transformer and optical potential transformer will be adopted in the near future, because of increasing demands of high accuracy and good reliability of current transformer and potential transformer. The application cases of optical current transformers and optical potential transformers are also introduced.

• Proceedings of the Optical Society of Korea Conference
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• 1997.08a
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• pp.111-113
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• 1997

The purpose of this paper is to propose a production flow for 155Mbps transmitter/receiver optical modules. Compact optical module packages for use as 155Mbps optical interfaces are developed by implementing a self-alignment principle for the formation of V-grooves and solder bumps. on the bases of experimental results of two hundreds of receiver/transmitter optical modules, each steps and flows of our production are developed by production efficiencies.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.5-6
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• 1989

The overall design of the optical isolator system is prepared for the 1 TW Nd pulse laser. Two pockels cell optical switches are employed to suppress the amplified spontaneous emission and the backward reflection. The role of two Farady rotators is to protect the laser system from the light amplified after back reflection. One saturable absorber dye and one liquid crystal polarizer/isolator will also serve as optical isolator.

• Journal of the Optical Society of Korea
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• v.6 no.4
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• pp.165-171
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• 2002

By using a semiconductor optical amplifier and a cross-phase modulation wavelength converter, fundamental all-optical logic gates including NOT, AND, NOR, XOR, and XNOR have been newly proposed and implemented. Realization of these all-optical logic gates will bring up not only all-optical networks but also all-optical computing and signal processing.

• Journal of the Optical Society of Korea
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• v.8 no.2
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• pp.90-95
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• 2004

The structure of Ti:LiNbO$_3$optical waveguide with a mode size far different from that of single mode optical fiber has been optimized by tapering the waveguide ends. This work was focused on determining the optimized sets of parameters for the fabrication of low-loss Ti indiffused optical waveguides in LiNbO$_3$. Numerical and analytical modeling were applied to simulate the guiding quality and to determine the mode sizes. Based on these modeling results, new waveguide structures with tapered ends have been defined, fabricated and characterized in the respect of the coupling of fiber to Ti-indiffused LiNbO$_3$waveguide.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.1
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• pp.47-53
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• 1999

CD-ROM(Compact Disk-Read Only Memory) is very attractive storage media because it has much storage space but is small size and portable. Optical pickup, one of the most important parts for reading data on a CD-ROM, is not produced tuned up. For the use of goods, we must tune up the optical pickup by adjusting the screw for adjustment. First, we developed analog servo system for optical pickup tuners. For eliminating some problems in analog servo system, this paper designed the modeling of digital servo system for optical pickup tuner. Though the characteristics of optical pickup are changed, the digital servo system for optical pickup tuner can easily apply to all pickup, and can reduce the measurement error among the optical pickup tuners. For the purpose of confirming the designed digital servo system, we produced data that specify the disk vibration and the disk eccentricity, and simulated servo system with MATLAB.

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.84-87
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• 2002

By using SOA (Semiconductor Optical Amplifier), all-optical XOR gate has been demonstrated at 5 Gb/s in RZ format. Firstly, Boolean AB-and Boolean AB have been obtained. Then, Boolean AB and Boolean AB have been combined to achieve the all-optical XOR gate, which has Boolean logic of AB+AB.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.229-234
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• 2007

Diffuse optical tomography (DOT) is a relatively new medical imaging modality which uses near infrared light to image large-sized tissues noninvasively. We constructed a frequency-domain DOT system to measure the optical properties of optical phantoms and human tissues. The FD-DOT uses the intensity-modulated infrared light source that illuminates the biological tissues. The phase shift and modulation changes at each detector site are separately processed to measure the optical properties. The absorption and scattering coefficients are separately estimated using inverse algorithms.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.169-174
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• 2006

The outstanding mechanical property of optical fiber and the merits of acoustic emission sensing technique are unified for novel sensor system. The generated ultrasonic wave from piezoelectric generator are propagated along the optical fiber and also sensed. The propagated wave can be influence by external pressure on the optical fiber or environmental circumstance. The optical fiber sensor using ultrasonic wave has advantages compare with existing sensor system. In this study, the sensitivity of the optical fiber sensor is experimentally investigated. As the applications of the optical fiber sensor system using piezoelectric ultrasonic waves, the point load on the optical fiber is measured and the monitoring system for the void fraction of two phase flows is developed. The experimental results show the linear relationship between sensed voltage and void fraction.