• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.273-274
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• 2007

• Journal of the Optical Society of Korea
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• v.20 no.4
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• pp.464-469
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• 2016

All-optical non-return-to-zero (NRZ) -to- return-to-zero (RZ) data-format conversion has been successfully demonstrated using a semiconductor optical amplifier in a fiber-loop mirror (so-called SOA-loop mirror) with a continuous-wave (CW) holding beam. The converted RZ signal after pulse compression has been used to create a 40 Gb/s OTDM (Optical Time Division Multiplexing) signal. Here is proposed an NRZ-to-RZ conversion method without any additional optical clocks, unlike conventional methods based on optical AND logic. In addition, it has the merit of operating at various bit-rate speeds without any controlling device. Moreover, it has a simple structure, and it can be used for all-optical bit-rate-flexible clock recovery.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1580-1584
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• 2009

We have theoretically analyzed the monolithic integration of vertical cavity lasers with depleted optical thyristor (VCL-DOT) structure and experimentally demonstrated optical logic gates such as AND-gate, OR-gate, and INVERTER implemented by VCL-DOT for an optical programmable gate array. The optical AND and OR gates have been realized by changing a input bias of the single VCL-DOTs and all kinds of optical logic functions are also implemented by adjusting an intensity of the reference input beams into the differential VCL-DOTs. To achieve the high sensitivity, high slope efficiency and low threshold current, a small active region of lasing part and a wide detecting area are simultaneously designed by using a selective oxidation process. The fabricated devices clearly show nonlinear s-shaped current-voltage characteristics and lasing characteristics of a low threshold current with 0.65 mA and output spectrum at 854 nm.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.168-169
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.182-183
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.337-338
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• 2007

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.262-263
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• 2004

• 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 the Optical Society of Korea
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• v.18 no.1
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• pp.65-70
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• 2014

This paper presents the simulation and design of an all-optical subtractor using a quantum-dot semiconductor optical amplifier Mach-Zehnder interferometer (QD-SOA MZI) structure consisting of two cascaded switches, the first of which produces the differential bit. Then the second switch produces the borrow bit by using the output of the first switch and the subtrahend data stream. Simulation results were obtained by solving the rate equations of the QD-SOA. The effects of QD-SOA length, peak power and current density have been investigated. The designed gate can operate at speeds of over 250 Gb/s. The simulation results demonstrate a high extinction ratio and a clear and wide-opening eye diagram.

• Korean Journal of Optics and Photonics
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• v.14 no.5
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• pp.535-544
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• 2003

The sensitivity analysis of a middle wave infrared optical system with 20: 1 zoom ratio is performed to analyze manufacturing and alignment tolerances, and to establish the alignment logic and the focus control strategy. The characteristics of the sensitivities of Zernike coefficients are investigated to all mechanical displacements and several zoom positions using Code-V Macro. From this result, the tolerances of manufacturing and alignment of the optical system are derived and the effective alignment logic is established. Futhermore, an effective focus control strategy is established to make the system simple and compact.