• Transactions of the Society of Information Storage Systems
• /
• v.2 no.1
• /
• pp.1-6
• /
• 2006

An optical ROM card system which using an optical probe array generated by Talbot effect was proposed as new robust storage solution. To improve the optical density and to decrease the power consumption of the system, it is very important to make the spot sizes of optical probes smaller as well as to increase the optical efficiency from the light source to optical probes. In this study, a microlens illuminated aperture array for generating high efficiency optical probe away with small beam spot was designed and fabricated using monolithic lithography integration method. The maximum intensity of optical probes of microlens illuminated aperture array increased about 12 times of that of aperture array, and the full width half maximum of the optical probe at Talbot plane generated by microlens illuminated aperture array was $0.77{\mu}m$.

• Current Optics and Photonics
• /
• v.4 no.6
• /
• pp.571-575
• /
• 2020

Optical wireless power transmission (OWPT) is a good candidate for long-distance underwater wireless power transmission. In this work we investigate the transmission efficiency of underwater OWPT, depending on the operating wavelength. We consider four operating wavelengths: infrared, red, green, and blue. We also consider the cases of pure water and sea water for the working conditions. Our results show that it is necessary to select the operating wavelength of underwater OWPT according to the transmission distance and water type of the target application.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1339-1342
• /
• 2006

We focused on improving of the optical efficiency in the direct BLU. We could achieve the optical efficiency by reducing the thickness of BLU and processing the prism shapes on a reflection sheet. And we were able to reduce the Lamps.

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.02a
• /
• pp.221-222
• /
• 2008

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.966-969
• /
• 2006

An optical model based on the optical thin-film theory is derived to calculate the output radiance of small molecules organic light-emitting diodes (OLEDs). We have designed the high efficiency OLEDs using the reflectance phase control of dielectric layers. It is found that OLED with a single $TiO_2$ dielectric layer is a good candidate to enhance the outcoupling efficiency and increase the color purity.

• Korean Journal of Optics and Photonics
• /
• v.34 no.6
• /
• pp.235-240
• /
• 2023

The optical signal injected into an end-fire optical phased array propagates along the waveguides inside the device and is emitted from the edge of the antenna. In general, reflection and scattering occur at the boundary, thereby reducing the emission efficiency of the optical signal. In this article, we propose a silicon nitride (Si₃N₄) tapered waveguide antenna structure whose width is tapered toward the emitting edge, achieving high emission efficiency operating at the 1,550 nm wavelength. The Si₃N₄ tapered waveguide antenna was numerically designed using the 3D finite-difference time-domain method. The optical signal emission efficiency increased from 78% to 96.3%, while reflectance decreased from 22% to 3.7% compared with the untapered waveguide antenna counterpart. This result will not only boost the optical signal intensity but also mitigate optical noise resulting from back reflection along the waveguide in the end-fire optical phased array device.

• Journal of the Optical Society of Korea
• /
• v.16 no.3
• /
• pp.247-255
• /
• 2012

Daylighting has a very effective role in reducing power consumption and improving indoor environments in office buildings. Previously, it was not under consideration as a major source of renewable energy due to poor reliability in the design. Optical fiber as a transmission medium in the daylighting system demands uniform distribution of light to solve cost, heat, and efficiency issues. Therefore, this study focuses on the uniform distribution of sunlight through the fiber bundle and to the interior of the building. To this end, two efficient approaches for the fiber-based daylighting system are presented. The first approach consists of a parabolic mirror, and the second approach contains a Fresnel lens. Sunlight is captured, guided, and distributed through the concentrator, optical fibers, and lenses, respectively. At the capturing stage, uniform illumination solves the heat problem, which has critical importance in making the system cost-effective by introducing plastic optical fibers. The efficiency of the system is increased by collimated light, which helps to insert maximum light into the optical fibers. Furthermore, we find that the hybrid system of combining sunlight and light emitting diode light gives better illumination levels than that of traditional lighting systems. Simulation and experimental results have shown that the efficiency of the system is better than previous fiber-based daylighting systems.

• Current Optics and Photonics
• /
• v.1 no.2
• /
• pp.101-106
• /
• 2017

Optical structures of a tapered ultra-thin light guide film (LGF) were optimized by optical simulation for increasing coupling efficiency between light sources and the LGF. A serration pattern on the entrance side surface could provide a comparable coupling efficiency to that of the conventional LGF where a linear, asymmetric prism array was formed on the taper surface. Several micro-patterns were applied to the top and/or bottom surface of the LGF for achieving better luminance property, and it was found that an optimized micro-pyramid pattern exhibited the highest average luminance together with satisfactory luminance uniformity.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.16 no.4
• /
• pp.22-26
• /
• 1979

Microlenses with an extremely small radius of curvature are efficiently use d to couple LED/laser diode light into optica1 fiber. We propose a Tapered lens for the highly efficient coupling of the optical fiber communication light souses into the fiber. Ray optical analysis shows that the maximum coupling efficiency is as high as 90 %, Tapered lens with optimum parameters are fabricated by using heating and pulling technique. Experiment shows that this new technique improves the coupling efficiency by two and four times for LED and laser diode, respectively, as compared with the simple flat - end coupling.

• Journal of the Optical Society of Korea
• /
• v.20 no.5
• /
• pp.623-627
• /
• 2016

A power-adjustable fully-integrated CMOS optical receiver with multi-rate clock-and-data recovery circuit is presented in standard 65-nm CMOS technology. With supply voltage scaling, key features of the optical receiver such as bandwidth, power efficiency, and optical sensitivity can be automatically optimized according to the bit rates. The prototype receiver has −23.7 dBm to −15.4 dBm of optical sensitivity for 10⁻⁹ bit error rate with constant conversion gain around all target bit rates from 1.62Gbps to 8.1 Gbps. Power efficiency is less than 9.3 pJ/bit over all operating ranges.