Multiple-Bit Encodings of Bragg Photonic-structures by Using Consecutive Etch with Various Square Wave Currents

이보연,황민우,조현,김희철,조성동 조선대학교 기초과학연구원 2011 조선자연과학논문집 Vol.4 No.3

New method to encode multiple photonic features of Bragg type reflector on silicon wafer has been investigated. Multiple bit encodes of distributed Bragg reflector features have been prepared by electrochemical etching of crystalline silicon by using various square wave current densities. Optical characterization of multi-encoding of distributed Bragg reflectors on porous silicon was achieved by Ocean optics 2000 spectrometer for the search of possible applications of multiple bit encoding of distributed Bragg reflectors such as multiplexed assays and chemical sensors. The morphology and cross-sectional structure of multi-encoded distributed Bragg reflectors was investigated by field emission scanning electron micrograph.

고해상도 ISAR 영상을 위한 광자 기반 FMCW 송수신 시스템 설계

류성준(Sungjun Yoo),배영석(Youngseok Bae),이민우(Minwoo Yi),장성훈(Sunghoon Jang),유준형(Joon Hyung Ryoo),남정빈(Jeongbin Nam),신진우(Jinwoo Shin) 한국전자파학회 2021 한국전자파학회논문지 Vol.32 No.3

본 논문에서는 고해상도 ISAR(inverse synthetic aperture radar) 영상을 위한 광자 기반 레이다용 송수신 시스템 설계기술을 제안하였다. 제안된 광자 기반 레이다 송수신 시스템은 광소자를 이용하여 광대역 특성의 파형을 도출하였으며, 레이다 송수신 시스템의 대역폭 특성에 따른 표적 탐지 성능을 레이다 시스템의 모델링 및 시뮬레이션을 통해 확인하였다. 최종적으로 이를 검증하기 위해 제안된 송수신 시스템을 제작하고, 소형 표적인 드론을 이용하였으며, 제안된 송수신 시스템의 대역폭이 증가함에 따라 고해상도 ISAR 영상 획득이 가능함을 확인하였다. This paper proposes a design for a photonics-based radar system for high-resolution inverse synthetic-aperture radar (ISAR) images. The proposed radar system can derive broadband characteristics using optical elements, such as phase modulator, laser source, and dual parallel Mach-Zehnder modulator (DPMZM). The detection performance and ISAR images for the target are observed according to the bandwidth of the radar system using modeling and simulation (M&S) for the proposed radar system. To verify the effectiveness of the bandwidth of the radar system, the proposed radar system are fabricated, and its performances are measured using a small drone in a practical environment. The results prove that the proposed FMCW radar system is a suitable candidate to overcome the limitations of bandwidth and high resolution.

Multiple-Bit Encodings of Bragg Photonic-structures by Using Consecutive Etch with Various Square Wave Currents

Lee, Bo-Yeon,Hwang, Minwoo,Cho, Hyun,Kim, Hee-Chol,Cho, Sungdong The Basic Science Institute Chosun University 2011 조선자연과학논문집 Vol.4 No.3

New method to encode multiple photonic features of Bragg type reflector on silicon wafer has been investigated. Multiple bit encodes of distributed Bragg reflector features have been prepared by electrochemical etching of crystalline silicon by using various square wave current densities. Optical characterization of multi-encoding of distributed Bragg reflectors on porous silicon was achieved by Ocean optics 2000 spectrometer for the search of possible applications of multiple bit encoding of distributed Bragg reflectors such as multiplexed assays and chemical sensors. The morphology and cross-sectional structure of multi-encoded distributed Bragg reflectors was investigated by field emission scanning electron micrograph.

[테라헤라츠 분야] 테라헤르츠 펄스 기술

한해욱,유난이,전태인,진윤식,박익모,김정회,문기원,한연호,정은아,강철,이영락,고도경,이의수,지영빈,김근주,한경호 한국전자파학회 2008 전자파기술 Vol.19 No.5

최근 테라헤르츠 펄스 기술을 근간으로 하는 테라헤르츠 포토닉스 분야는 새로운 연구 주제로서 전세계적으로 큰 관심을 모으고 있다. 단지 순수과학적 측면에서 뿐만 아니라 상업적 응용 가능성이 높아짐에 따라 많은 선진국에서는 테라헤르츠 포토닉스의 발전을 위해 지대한 노력을 경주하고 있다. 저명한 국제 학술지와 국제 학회에서 테라헤르츠 펄스기술에 대한 논문의 수가 폭발적으로 증가하고 있다는 것은 이러한 사실을 뒷받침하고 있다. 테라헤르츠 응용 기술은 테라헤르츠 펄스 광원과 검출기, 그리고 관련된 수동 소자의 개발이 선행되어야 한다. 따라서 본 논문에서는 테라헤르츠 광전도 안테나, 광정류, 준위상 정합 기반 차주파수 발생, 전광 샘플링, 고속 실시간 측정, 테라헤르츠 전송선, 그리고 각종 도파로 구조와 같은 기초적이면서 핵심적인 소자와 측정 기술에 대하여 간략히 기술하고자 한다. In recent years, the field of ㎔ photonics based on ㎔ pulse technology has gained tremendous, worldwide interest as a new exciting research subject. With a possibility of many commercial applications as well as fundamental scientific achievements in the field, many advanced nations are stepping up their effort in advancing the field of ㎔ photonics. This fact is supported by the observation of the significant increase in the number of papers on ㎔ pulse technology presented in renowned international journals and conferences. The subject that is interesting for the ㎔ application is the development of ㎔ pulse sources and detectors, and other passive devices. In this paper, we present a brief review on some of the key devices and their relavant measurement techniques such as ㎔ photoconductive antennas, optical rectificaton, difference frequency geneneration with quasi-phase matching structures, electrooptic sampling, high speed real time measurements, ㎔ transmission lines, and other various waveguide structures.

Large Electroabsorption Susceptibility Mediated by Internal Photoconductive Gain in Ge Nanowires

Lee, Hyun-Seung,Kim, Cheol-Joo,Lee, Donghun,Lee, Ru Ri,Kang, Kibum,Hwang, Inchan,Jo, Moon-Ho American Chemical Society 2012 NANO LETTERS Vol.12 No.11

<P>Large spectral modulation in the photon-to-electron conversion near the absorption band-edge of a semiconductor by an applied electrical field can be a basis for efficient electro-optical modulators. This electro-absorption effect in Group IV semiconductors is, however, inherently weak, and this poses the technological challenges for their electro-photonic integration. Here we report unprecedentedly large electro-absorption susceptibility at the direct band-edge of intrinsic Ge nanowire (NW) photodetectors, which is strongly diameter-dependent. We provide evidence that the large spectral shift at the 1.55 μm wavelength, enhanced up to 20 times larger than Ge bulk crystals, is attributed to the internal Franz–Keldysh effect across the NW surface field of ∼10<SUP>5</SUP> V/cm, mediated by the strong photoconductive gain. This classical size-effect operating at the nanometer scale is universal, regardless of the choice of materials, and thus suggests general implications for the monolithic integration of Group IV photonic circuits.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-11/nl3033203/production/images/medium/nl-2012-033203_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl3033203'>ACS Electronic Supporting Info</A></P>

Multiple-Bit Encodings of Bragg Photonic-structures by Using Consecutive Etch with Various Square Wave Currents

Bo-Yeon Lee,Minwoo Hwang,Hyun Cho,Hee-Chol Kim,Sungdong Ch 조선대학교 기초과학연구원 2011 조선자연과학논문집 Vol.4 No.3

국내 광(光)산업의 기술발전이 관련산업 수출입에 미치는 영향

진현정(Hyun-Joung Jin),권혁인(Hyeong-In Kwon),채예린(Ye-Rin Che) 한국무역연구원 2021 무역연구 Vol.17 No.1

Purpose This study analyzed the effects of technological development in the domestic photonics industry on the economy of South Korea and other countries. Design/Methodology/Approach The GTAP (Global Trade Analysis Project) model was used among computable general equilibrium (CGE) models that can explain not only interactions by economic sectors but also changes in macroeconomic variables. Findings Empirical results showed that if productivity increases due to the technological development of Korea’s photonics industry;economic indicators such as GDP and exports volume improve. Second;production and sales volume of the domestic photonics industry increased;but the market price index of the sector fall. This is probably because labor;land;and capital become more concentrated in the photonics industry due to increased productivity of the sector. Third;as the technological development level of the photonics industry grows;import increase exceeds export increase. The increase in imports is believed to be due to relatively high dependence of the downstream industry on imports. Research Implications This study contributes to the extant literature in analyzing how technological changes in the photonics industry;which is said to be a core technology of the Fourth Industrial Revolution;affects domestic industries. It shows that if import dependence of the downstream industry of the sector remains high;increases in imports will be larger than increases in exports even if productivity increases. This suggests the need for the development of source technology and for expansion of support policy toward core parts of the photonics industry to lower import dependence of the photonics industry.

광산업체 입지와 사업네트워크 특성으로 본 광산업의 지역적 성장에 관한 연구

임영훈 ( Young Hun Lim ) 한국경제지리학회 2011 한국경제지리학회지 Vol.14 No.4

Focusing on the photonics industry as a new one and the photonics industry agglomeration in Gwangju, this study investigated the regional characteristics of the photonics industry`s growth. To analyze the location and business network of photonics firms as foundation of industrial growth, in-depth interviews were conducted. It also aimed to review the meanings of regional policy to promote a strategic industry. As a result, it founded the differential growth of the photonics industry in the Capital region(with a market advantage) and Gwangju(with a policy advantage). Gwangju`s regional policy had an importance that it formed a regional consensus and increased the momentum and variety to drive regional industrial development.

DEA 모형을 활용한 광주 광산업체 효율성 평가에 관한 연구

조건 ( Geon Cho ),정경호 ( Kyung Ho Jung ) 한국품질경영학회 2011 품질경영학회지 Vol.39 No.2

In this study, we try to evaluate the efficiency of the photonics industry using a data envelopment analysis(DEA) model. We first develope four stage procedures for selecting proper input and output variables which consist of selecting the first candidate variables from literature survey, selecting the second candidate variables through experts` discussion, measuring the partial efficiency of the selected variables based on Tofallis` profiling, and clustering some variables through the rank correlation analysis of partial efficiency proposed by Mm and Kim(1998). With this procedure, we select 4 input variables(capital, number of employee, R&D cost, operating cost) and 2 output variables(sales, growth of sales) and then utilize CCR and BCC model to measure efficiencies of 26 photonics companies in Gwangju. Moreover, we perform the reference group analysis to figure out what causes inefficiencies and to provide the desirable values for input and output variables at which inefficient photonics companies become efficient. Finally, we classify 26 photonics companies into three groups such as optical communications, optical applications, and optical sources, and perform the Kruskal-Wallis test to check if there exist some differences between efficiencies of three groups.

Chirality in Non-Hermitian Photonics

유선규,Xianji Piao,박남규 한국광학회 2019 Current Optics and Photonics Vol.3 No.4

Chirality is ubiquitous in physics and biology from microscopic to macroscopic phenomena, such as fermionic interactions and DNA duplication. In photonics, chirality has traditionally represented differentiated optical responses for right and left circular polarizations. This definition of optical chirality in the polarization domain includes handedness-dependent phase velocities or optical absorption inside chiral media, which enable polarimetry for measuring the material concentration and circular dichroism spectroscopy for sensing biological or chemical enantiomers. Recently, the emerging field of non-Hermitian photonics, which explores exotic phenomena in gain or loss media, has provided a new viewpoint on chirality in photonics that is not restricted to the traditional polarization domain but is extended to other physical quantities such as the orbital angular momentum, propagation direction, and system parameter space. Here, we introduce recent milestones in chiral light-matter interactions in non-Hermitian photonics and show an enhanced degree of design freedom in photonic devices for spin and orbital angular momenta, directionality, and asymmetric modal conversion.