• Current Optics and Photonics
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• v.2 no.6
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• pp.540-546
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• 2018

We propose an implementation scheme for an optical encryption system with hybrid-pattern random keys. In the encryption process, a pair of random phase keys composed of a white-noise phase key and a structured phase key are positioned in the input plane and Fourier-spectrum plane respectively. The output image is recoverable by digital reconstruction, using the conjugate of the encryption key in the Fourier-spectrum plane. We discuss the system encryption performance when different combinations of phase-key pairs are used. To measure the effectiveness of the proposed method, we calculate the statistical indicators between original and encrypted images. The results are compared to those generated from a classical double random phase encoding. Computer simulations are presented to show the validity of the method.

• Korean Journal of Optics and Photonics
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• v.17 no.3
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• pp.240-247
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• 2006

This paper discusses the optical system design for projection TV using LCOS type micro display, which provides the high resolution, slim depth, and a large screen of more than 60 inches. We analyzed the relationship between the illumination system, projection lens, color separation & recombination system, and micro display. From this quantitative analysis, the starting data for the optimum light engine was defined, and all optical systems were designed by an optimization process. Three RGB panels were proposed for a high luminence system, and the four prisms symmetrically located make equal optical path lengths for the RGB rays. This color separation & recombination system enables the a compact illumination system. Also, in order to the slim light engine with high resolution, the folded projection lens system was designed by inserting a mirror between projection lenses.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.885-887
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• 2005

Recently, many three-dimensional micros-structures were fabricated using micro-stereolithography technology. However, for most conventional micro-stereolithography apparatus. an expensive laser was used as light source and complex optical systems were used. In this research. new type of micro-stereolithography apparatus which has UV lamp as light source and optical fiber as beam delivery system was developed. This apparatus is cheaper and simpler then conventional micro-stereolithography apparatus.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.20-21
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• 2003

Erbium doped fiber (EDF) sources are useful devices for characterization of optical components for wavelength division multiplexing (WDM) fiber optic communication system. Therefore, there are many efforts to extend the bandwidth and to increase the power of the light source. Especially, L-band ASE source uses the low inversion state of EDF. It makes the power efficiency very low and needs a lot of fiber as several times as the fiber needed in C-band ASE generation. (omitted)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.161-162
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• 2006

Micro-stereolithography technology is used for fabricating of 3-dimensional micro-structures. In some cases, this technology is more economical and simpler than MEMS and LIGA technologies based on semiconductor process. In this research, the micro-sterolithography apparatus that is more economical and simpler than current micro-stereolithography apparatus was developed. This apparatus uses UV lamp and optical fiber as a light source and tight delivery system, respectively.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.236-243
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• 2003

We discussed the design of lens module schematic eyes equivalent to finite model eyes, which are used to model the human eye based on spherical aberration and Stiles-Crowford effect. The optical system for head mounted display (HMD) is designed and evaluated using lens module schematic eyes. In addition to a compact HMD system, an optical system with high Performance is required. To satisfy these requirements, we used diffractive optical elements and aspheric surfaces so that the color and mono-chromatic aberrations were corrected. The optical system for HMD is composed of 0.47 inch micro-display of SVGA grade with 480,000 pixels, a plastic hybrid lens for the virtual image, and the lens module schematic eyes. The designed optical system fulfills the current specifications of HMD: such as, EFL of 31.25 mm, FOV of 24H$\times$18V$\times$30D degrees, and overall length of 59.1 mm. As a result, we could design an optical system useful for HMD; the system is expected to be comfortable while the user wears it.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.308-309
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• 2003

최근 광통신의 발전은 광 통신 소자의 제작시 집적화, 소형화, 경량화 그리고 저가격화를 원하게 되었다. 이러한 문제점을 해결하기 위해, 기판 위에 광소자를 집적하는 미세 광학 벤치 (Micro Optical Bench)에 대한 많은 연구가 진행되고 있는 중이다. MEMS(Micro Electro Mechanical System) 공정기술인 벌크(bulk) 마이크로 머시닝 기술을 이용함으로서 하나의 기판 위에 광소자들을 조립하는 미세 광학 벤치를 구현 할 수 있다. (중략)

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1526-1531
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• 2007

Data transmission capacity that is required in 2010 is forecasted that increase by optical communication capacity more than present centuple, and is doing increased demand of optical communication related industry product present. Specially, Lid glass' application that is one of optical communication parts is used in optical communication parts manufacture of Fiber array, Ferrule array, Fanout Black, Silica optical waveguide chip and splitter etc. Also, it is used widely for communication network system, CATV, ATM-PON, FTTH and system. But, Lid glass need much processing times and becomes cause in rising prices of optical communication parts because production cost is expensive. The objectives, of this work is to suggest the micro concave and convex pattern manufacturing technology on borosilicate plate using high temperature and compression molding method. As a result, could developed micro pattern Mold more than 5 pattern, and reduce Lid Glass manufacture cycle time.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2263-2265
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• 2000

본 연구에서는 광 픽업의 소형, 경량 제작을 위해 MEMS 기술을 이용하여 planar micro optics 방법으로 광 픽업을 구성하는 micro lens, actuator, beamsplitter 등을 설계, 제작하고 집적화한 픽업헤드를 구성하여 그 특성을 분석하였다. 특성분석 결과 disk에 focusing 되는 beam의 형상은 circle type의 비교적 양호한 결과를 얻을 수 있었고 beam spot size는 약 22$\mu m$로 실제 system에서 요구되는 0.9$\mu m$이내의 beam spot size에 비해 약 25배 가량 큰 beam spot size를 얻을 수 있었다.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.11
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• pp.654-659
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• 2005

An improved power supply for APD(Avalanche Photo Diode) with a received optical power monitoring circuit allows the received optical power increase temporary without of the degradation of the electrical signal. For the cost reduction and simple fabrication, an improved power supply has been proposed that it was designed for driving a APD as a receiving device of a wireless optical transmission system. It was demonstrated that it was possible to improve a dynamic range by compensating the temperature coefficient of the APD up to 1.0 V/$^{\circ}C$ through the power supply. Also, for an efficient transmission at the receiver end, a simple structure of a single cylindrical micro-lens configuration was used in conjunction with the laser diode to partially compensate a laser beam ellipticity. For this purpose, an astigmatism introduced by the micro-lens is utilized for the additional compensation of the beam ellipticity at the receiver end. In this paper, it is demonstrated that an efficient beam shaping is realized by using the proposed configuration consisting of the single lens attached to the laser diode.