• Journal of the Optical Society of Korea
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• 제13권4호
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• pp.456-463
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• 2009

We introduce a holographic data storage system for intermediating between small data sets and mass holographic data recording. It employs a holographic sequentially superimposed recording technique. We discuss a time scheduling technique for making uniform reconstruction of sequentially recorded holograms and we show experimental results. We also discuss the Bragg selectivity of sequentially recorded holograms. The maximum storage density of our system is estimated to be 224kbit/$mm^2$. Our system is useful as an intermediate recording system before recording mass holographic data in a larger system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.678-681
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• 2003

In conventional optical data storage numerical aperture (NA) cannot be over 1 because of diffraction limit. To overcome this limitation. solid immersion lens(SIL) have produced a great interest in near-field optical data storage. In conventional optical recording method, the dual lens system using object lens and SIL had been studied generally. But the conventional SIL system has some critical problems that must be solved. The problems are heat, contamination. alignment of optical components and so on. To solve these problems. this work proposes enhanced SIL which has several advantages for mechanical and optical issues. This new SIL system named elliptic SIL(ESIL) can use evanescent energy in near-field more effectively. In addition. because of applying the inside recording unlike previous surface recording, ESIL can clear up the problems. The design and analysis of ESIL art executed by using CODE V. Also, in this paper we composed actual data recording system and achieved recording experiment by applying ESIL to magneto-optical recording. In conclusion. we analyze the improvement of aerial density and the reasonability of application to real data storage system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.2142-2143
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• 2006

Today any data storage system cannot satisfy all of these conditions, however holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System can be constructed without mechanically actuating part therefore fast data transfer rate and high storage capacity about 1Tb/cm3 can be realized. In this research, to reduce errors of binary data stored in holographic data storage system, a new method for bit error reduction is suggested. Firstly, find fuzzy rule to use test bed system for Element of Holographic Digital Data System. Secondly, make fuzzy rule table using DNA coding method. Finally, reduce prior error element and recording digital data. Recording ratio and reconstruction ratio show good performance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1260-1263
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• 2005

Data storage related with writing and retrieving requires high storage capacity, fast transfer rate and less access time. Today any data storage system cannot satisfy these conditions, however holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System can be constructed without mechanical actuating part therefore fast data transfer rate and high storage capacity about 1Tb/cm3 can be realized. In this research, to reduce errors of binary data stored in holographic data storage system, a new method for bit error reduction is suggested. First, find fuzzy rule using experimental system for Element of Holographic Digital Data System. Second, make fuzzy rule table using Genetic algorithm. Third, reduce prior error element and recording Digital Data. Recording ratio and reconstruction ratio will be very good performance

• 정보저장시스템학회논문집
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• 제7권1호
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• pp.1-6
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• 2011

A control method for the angle servo of reference beam during reading recoded data images of a holographic data storage system is presented. The recording scheme with angle offset is adopted in order to verify the proposed angle servo. Using this recording scheme, the angle error signal is generated and we can implement the angle servo. Experiments have been performed on recording and reading data images to compensate Bragg angle mismatch.

• 융합정보논문지
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• 제9권4호
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• pp.14-20
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• 2019

본 논문은 원 데이터를 암호화하여 URL(Uniform Resource Locator)정보 형식으로 변형하고, URL정보를 QR코드로 인코딩함으로써 원 데이터의 저장없이 QR코드를 매개로 데이터를 기록하고 해독할 수 있도록 하는 스마트한 QR코드에 의한 비저장식 데이터 기록 시스템 및 비저장식 데이터 제공방법을 제시하는 데 목적이 있다. 연구의 방법은 선행기술연구와 문헌조사를 통해 연구의 차별성을 두기 위한 방법을 제시했으며 분석결과, 온라인 관리서버에 구축되는 시스템으로서, 데이터 입력 신호별 매칭 암호가 저장된 암호DB, QR코드 생성 명령에 따라 입력데이터를 암호DB에서 매칭되는 암호정보로 치환하여 관리서버 도메인네임의 하위 로케이터로 결합시킨 URL정보로 변환시키고, URL정보를 QR코드로 인코딩하는 코드 생성부, 그리고 URL접속신호 수신에 따라, URL정보를 입력데이터로 변환 제공하는 암호 해독부를 포함하는 QR코드에 의한 비저장식 데이터 기록시스템을 제공한다. 따라서 스마트한 QR방식의 데이터관리방식(기록과 제공)은 사용의 편리성과 공간의 제약이나 용량사용의 장애가 없다는 점을 밝히고 있다.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.1-22
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• 2005

There are two important trends in the modern information society, including digital networking and ubiquitous environment. Thus it is strongly required to develop new information storage devices such as high density storages to match the increased data capacity and small size storage devices to be applied to the mobile multimedia electronics. So far, many approaches have been studied for the high density memory, including the holographic memory, super-RENS and near-field recording using solid immersion lens (SIL) or nano-probe for the ODD (Optical Disk Drive) system, and the perpendicular magnetic recording and heat-assisted magnetic recording for the HDD (Hard Disk Drive) system. In addition, new mobile storage devices have been prepared using 0.85" HDD and 30mm ODD systems from a lot of foreign and domestic companies and institutes. In this paper, the recent technology trend for the next generation information storage system is summarized to offer a research motivation and encouragement to new researchers in this field with an emphasis on the technical issues of the increase of data capacity and decrease of device size.

• 정보저장시스템학회논문집
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• 제3권1호
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• pp.1-4
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• 2007

A high density optical data storage device has been required for many years. In the field of the optical data storage, a near-field recording (NFR) technology is considered as a next generation one for achieving the high data density. Due to an evanescent wave effect occurred under 100nm distance which is the excessively small distance between the SIL and the disc, the most significant and difficult problem in this technology is to maintain a gap between a solid immersion lens (SIL) and a disc. Also, maintaining the gap under at least 50nm is required in the NFR gap servo system to use the evanescent wave effect efficiently. There are some institutes that have shown the novel gap servo control. In general, they use a mode switching servo method which consists of approach, hand-over and gap control mode. However there is a critical problem such as an overshoot at the tuning point from the approach mode to the hand-over mode, which may cause a collision between the SIL and the disc. In this paper, we show our NFR system and an improved gap servo system using an exponential function as the approach mode which can reduce the overshoot.

• 정보저장시스템학회논문집
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• 제3권1호
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• pp.13-16
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• 2007

The purpose of this paper is real time tilt servo control of the holographic data storage system. Holographic data storage device is a next generation data storage device with high storage density, high transfer rate and short access time. This device is very sensitive to a disturbance due to the enormous storage density. As to the recording material changed disc type, the media continuously vibrates as the disc rotates. When disc rotates, deviation, eccentricity and unbalance disturbance are occurred. This disturbances cause disc tilt, finally reference beam does not illuminates to correct incidence angle. Therefore real time tilt servo control is essential. In this paper, the algorithm is proposed to make real time tilt detection in angle multiplexing of the holographic data storage system with an additional servo beam and the experiments are performed.

• 정보저장시스템학회논문집
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• 제2권4호
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• pp.224-229
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• 2006

There has been studied flow to minimize the spot size to increase data capacity. Optical data storage devices are being developed near practical limits with wavelength and NA of 405nm and 0.85. There has been studied many types of next generation storage devices such as blu-ray multilayer system, probe based data storage and holographic data storage. Among these data storage devices, solid immersion lens(SIL) based near field recording (NFR) has been widely studied. In this system, SIL is the key component that focuses the laser beam with a very small size which enables ultra high data capacity. Therefore, optical performance evaluation system is required for SIL assembly. In this dissertation, a simple and accurate SIL assembly measurement method is proposed with wedge plate lateral shearing interferometer(LSI). Wedge plate LSI is cheaper than commercialized interferometer, robust to the vibration and the moving distance for phase shifting is large that is order of micrometer. We designed the thickness, wedge angle, material, surface quality and wavelength of wedge plate as 1mm, 0.02degree, fused silica, lamda/10(10-5) and 405nm, respectively. Also, we confirmed simulation and experimental results with quantitative analysis. This simple wedge plate LSI can be applied to different types of SIL such as solid immersion mirror(SIM), hemispherical, super-hemispherical and elliptical SIL.