• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.11
• /
• pp.65-67
• /
• 1996

Optical property of tissue is characterized by its high scattering of light. In near infrared range$(800{\sim}1200nm)$ scattering is dominant than absorption. Communication using NIR through tissue is applicable to immplantable device. In this paper, simulation of unit impulse response of light in tissue is carried out to estimate the amplitude, phaselength and phaselength deviation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.2
• /
• pp.167-172
• /
• 2007

In this paper, we analyzed the molecular behavior of IPS-LCDs and VA-LCDs by using numerical simulation. The numerical simulation was performed on the basis of Ericksen-Leslie continuum theory. To improve the accuracy of the calculation, we considered fluid balance equation and director balance equation at the same time. thus, we calculated the flow effect for both switching on and off states. As the results of simulation, we confirmed abnormal twist in IPS-LCDs and fast molecular behavior in VA-LCDs which could influence response time.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.10
• /
• pp.1860-1865
• /
• 2008

40Gbps WDMSystems have been studied by numerical simulation to optimize their performance. Standard single mode fiber is assumed, and the most popular modulation format, NRZ, is used for the study. These assumptions are valid when existing WDM systems are required to upgrade their performance to 40Gbps. It is shown that the standard single mode fiber can transmit optical signals over 4800 (BER < 10-15) by optimizing optical and electrical filter characteristics at the receiver and by compensation of dispersion. In addition, when the system performance is mainly limited by ASE noise of EDFAs, it is found that flattop-shaped optical filter at the receiver gives a better result than Gaussian-shaped filter unless the insertion loss of the optical filter is larger than 5dB.

• Korean Journal of Optics and Photonics
• /
• v.17 no.3
• /
• pp.248-255
• /
• 2006

Most optical security systems use a 4-f correlator, Mach-Zehnder interferometer, or a joint transform correlator(JTC). Of them, the JTC does not require an accurate optical alignment and has a good potential for real-time processing. In this paper, we propose an image encryption system using a position shift property of the JTC in the Fourier domain and a random phase image. Our encryption system uses two keys: one key is a random phase mask and the other key is a position shift factor. By using two keys, the proposed method can increase the security level of the encryption system. An encrypted image is produced by the Fourier transform for the multiplication image, which resulted from adding position shift functions to an original image, with a random phase mask. The random phase mask and position shift value are used as keys in decryption, simultaneously. For the decryption, both the encrypted image and the key image should be correctly located on the JTC. If the incorrect position shift value or the incorrect key image is used in decryption, the original information can not be obtained. To demonstrate the efficiency of the proposed system, computer simulation is performed. By analyzing the simulation results in the case of blocking of the encrypted image and affecting of the phase noise, we confirmed that the proposed method has a good tolerance to data loss. These results show that our system is very useful for the optical certification system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.12
• /
• pp.60-66
• /
• 2011

There are several technological problems have to be resolved for LEDs to be used as a general purpose light source. In addition, there are several differences between existing luminaires and the general planer LED luminaire for the intensity distribution. Therefore, the optical engineer then faces the challenging a problem of designing for a spatially extended and non-uniform light source. In the previous studies on the optical design of luminaires, a lot of studies on reflectors and light source have been conducted but the ones on prisms and lenses are insufficient at present. This study developed the numerical model of planar prism LED luminaire to control luminous intensity distribution of LED luminaires. And this study presents an optical calculation process for the prism optical design of a planar prism LED luminaire and a comparison of the simulation results between the developed numerical model and Photopia 2.0 to verify the accuracy of the numerical model. In addition, this study showed a method for the control of various luminous intensity distribution from the developed numerical model.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.1
• /
• pp.1-6
• /
• 2011

Optical gain characteristics of $1.3{\mu}m$ type-II GaAsSb/InGaNAs/GaAs trilayer quantum well structures were studied using multi-band effective mass theory. The results were compared with those of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structures. In the case of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure, the energy difference between the first two subbands in the valence band is smaller than that of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. Also, $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure shows larger optical gain than $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. This means that GaAsSb/InGaNAs/GaAs system is promising as long-wavelength optoelectronic devices for optical communication.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.223-223
• /
• 2009

In this paper, designed and simulated Power Splitter (PS) integrated Mach-Zehnder interferometer (MZI) based planar type optical waveguide devices (which is called here a PS-MZI). The PS-MZI optical waveguide sensor was preceded by a Y-junction, which splits the input power between the sensor, and a reference branch, to minimize the effect of optical power variations. The PS-MZI optical waveguide sensor induced changing phases of the incident beam, which had fallen upon the waveguide through computer simulation, according to the small changes in the index of refraction, thus beam intensity was changed. The waveguide were optimized at a wavelength of 1550 nm and fabricated according to the design rule of 0.45 delta%, which is the difference of refractive index between the core and clad. The fabrication of PS-MZI optical waveguide sensor was performed by a conventional planar lightwave circuit (PLC) fabrication process. The PS-MZI optical waveguide that was fabricated to be applied as a biosensor revealed a low insertion loss and a low polarization-dependent loss. After having etched the over-clad at the sensor part in the MZI optical waveguide that was fabricated, Ti deposition was made on the adhesion layer, and then Au thin-film deposition was carried out thereon. In addition, its optical properties were measured by having changed the index of refraction oil at the sensing part of the MZI. To apply the planar type PS-MZI optical waveguide as a biosensor, a detection test for Staphylococcus aureus was conducted according to changes in concentration, having adopted Ti-alkoxide as ligand. The detection result of the S. aureus by the PS-MZI optical waveguide sensor was possible to the level of $10^1$ CFU/ml.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.3
• /
• pp.261-268
• /
• 2014

Precision screws have a wide range of industrial applications such as electrical and automotive products. To produce screw threads with high precision, not only high precision manufacturing technology but also reliable measurement technology is required. Machine vision systems have been used in the automatic inspection of screw threads based on backlight illumination, which cannot detect defects on the thread surface. Recently, an omnidirectional inspection system for screw threads was developed to obtain $360^{\circ}$ images of screws, based on front light illumination. In this study, the illumination design for the omnidirectional inspection system was modified by adding a light shield to improve the image uniformity. Optical simulation for various shield designs was performed to analyze image uniformity of the obtained images. The simulation results were analyzed statistically using response surface method, from which optical performance of the omnidirectional inspection system could be optimized in terms of image quality and uniformity.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.231-234
• /
• 2008

In this paper, we propose a novel electrode structure for superb transmittance in super in-plane switching (S-IPS) mode while keeping the features of the conventional SIPS mode such as the capability of initial LC alignment. The optimization of the electrode made it possible to enhance the light transmittance approximately by 14 % in comparison to the conventional S-IPS cell.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.2 no.1
• /
• pp.82-86
• /
• 2002

It is demonstrated that the conventional current-pulse laser drivers are not adequate in driving VCSELs operating at multi-Gb/s speeds. Simulation results, including the bonding parasitics, show that high-performance VCSELs are more efficiently driven using voltage-pulse mode of operation. The optical output power is almost doubled in the voltage-mode of operation, while the total electrical power consumption of the transmitter decreases by 20%.