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Author

Deok Ha Woo

Bio: Deok Ha Woo is an academic researcher from Korea Institute of Science and Technology. The author has contributed to research in topics: Optical amplifier & Optical switch. The author has an hindex of 16, co-authored 170 publications receiving 1364 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a cross-gain modulation of semiconductor optical amplifiers has been proposed and demonstrated successfully at 10 Gb/s for all-optical XOR gates.
Abstract: The novel design of an all-optical XOR gate by using cross-gain modulation of semiconductor optical amplifiers has been suggested and demonstrated successfully at 10 Gb/s. Boolean AB~ and A~B of the two input signals A and B have been obtained and combined to achieve the all-optical XOR gate. No additional input beam such as a clock signal or continuous wave light is used in this new design, which is required in other all-optical XOR gates.

215 citations

Journal ArticleDOI
TL;DR: In this article, the authors have successfully designed and fabricated a significantly shortened multimode interference coupler for application in polarization splitter, using a phenomenon that they termed "quasi-state" (QS) imaging effect.
Abstract: We report that we have successfully designed and fabricated a significantly shortened multimode interference coupler for application in polarization splitter, using a phenomenon that we termed "quasi-state" (QS) imaging effect. First, we identified and analyzed the QS imaging effect, and, based on the QS analysis, designed and fabricated a novel multimode interference (MMI) device with its split length shortened to 1/5 of a normally designed MMI split length. The fabrication is simple and cost effective and the fabricated device shows outstanding characteristics in extinction ratio, signal homogeneity, excess loss, and tolerance in the length of the splitter.

112 citations

Journal ArticleDOI
TL;DR: In this article, an all-optical half adder using semiconductor optical amplifier based devices is suggested and demonstrated at 10 Gbit/s, where Boolean AB and AB are obtained and combined to achieve logic SUM.

99 citations

Journal ArticleDOI
TL;DR: The proposed sensitive and selective terahertz detection method can provide abundant information of detected biomaterials to help deep understanding of fundamental optical characteristics of them, suggesting rapid diagnosis way especially useful for such dangerous and time-sensitive target biommaterials.
Abstract: As a candidate for a rapid detection of biomaterials, terahertz (THz) spectroscopy system can be considered with some advantage in non-destructive, label-free, and non-contact manner. Because protein-ligand binding energy is in the THz range, especially, most important conformational information in molecular interactions can be captured by THz electromagnetic wave. Based on the THz time-domain spectroscopy system, THz nano-metamaterial sensing chips were prepared for great enhancing of detection sensitivity. A metamaterial sensing chip was designed for increasing of absorption cross section of the target sample, related to the transmitted THz near field enhancement via the composition of metamaterial. The measured THz optical properties were then analyzed in terms of refractive index and absorption coefficient, and compared with simulation results. Also, virus quantification regarding various concentrations of the viruses was performed, showing a clear linearity. The proposed sensitive and selective THz detection method can provide abundant information of detected biomaterials to help deep understanding of fundamental optical characteristics of them, suggesting rapid diagnosis way especially useful for such dangerous and time-sensitive target biomaterials.

81 citations

Journal ArticleDOI
TL;DR: By using the gain nonlinearity characteristics of semiconductor optical amplifier, an all-optical binary half adder at 10 Gbps is demonstrated and the possibilities for the enhanced complex logic operation and higher chances for multiple logic integration are explored.
Abstract: By using the gain nonlinearity characteristics of semiconductor optical amplifier, an all-optical binary half adder at 10 Gbps is demonstrated. The half adder operates in a single mechanism, which is cross gain modulation. The half adder utilizes two logic functions of SUM and CARRY, which can be demonstrated by using XOR and AND gates, respectively. The extinction ratios of both XOR and AND gates are about 6.1 dB. By achieving this experiment, we also explored the possibilities for the enhanced complex logic operation and higher chances for multiple logic integration.

72 citations


Cited by
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Proceedings Article
01 Jan 1999
TL;DR: In this paper, the authors describe photonic crystals as the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures, and the interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.
Abstract: The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

2,722 citations

Journal ArticleDOI
TL;DR: Graphene materials have been widely explored for the fabrication of gas sensors because of their atom-thick two-dimensional conjugated structures, high conductivity and large specific surface areas.
Abstract: Graphene materials have been widely explored for the fabrication of gas sensors because of their atom-thick two-dimensional conjugated structures, high conductivity and large specific surface areas. This feature article summarizes the recent advancements on the synthesis of graphene materials for this purpose and the techniques applied for fabricating gas sensors. The effects of the compositions, structural defects and morphologies of graphene-based sensing layers and the configurations of sensing devices on the performances of gas sensors will also be discussed.

912 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used an inverse design algorithm and experimentally demonstrated an integrated polarization beamsplitter with a footprint of 2.4×××2.4 μm2.
Abstract: Researchers used an inverse design algorithm and experimentally demonstrated an integrated polarization beamsplitter with a footprint of 2.4 × 2.4 μm2.

594 citations