• Proceedings of the Optical Society of Korea Conference
• /
• 2009.10a
• /
• pp.394-395
• /
• 2009

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.05b
• /
• pp.327-330
• /
• 2000

The scanning Maxwell-stress microscopy (SMM) is a dynamic noncontact electric force microscopy that allows simultaneous access to the electrical properties of molecular system such as surface potential, surface charge, dielectric constant and conductivity along with the topography. The Scanning near-field optical / atomic force microscopy (SNOAM) is a new tool for surface imaging which was introduced as one application of the atomic force microscope (AFM). Operated with non-contact forces between the optical fiber and sample as well as equipped with the piezoscanners, the instrument reports on surface topology without damaging or modifying the surface for measuring of optical characteristic in the films. We report our recent results of its application to nanoscopic study of domain structures and electrical functionality in organic thin films by SMM. Furthermore, we have illustrated the SNOAM image in obtaining the merocyanine dye films as well as the optical image.

• Journal of Sensor Science and Technology
• /
• v.10 no.1
• /
• pp.9-15
• /
• 2001

The extrinsic Fabry-Perot interferometric (EFPI) optical fiber sensor shows good sensitivity and resolution, and has many advantages over optical fiber sensors of other types. However, this EFPI optical fiber sensor has a disadvantage that the distinction of measuring directions is difficult due to the measurement method by using only fringe counting. In this paper, the transmission-type extrinsic Fabry-Perot interferometric (TEFPI) optical fiber sensor was developed, which has been improved by the additional function and whose measuring system is different from that of the conventional EFPI optical fiber sensor. Then the application result of the TEFPI optical fiber sensor to the strain and temperature measurement was explained in detail.

• Korean Journal of Optics and Photonics
• /
• v.14 no.6
• /
• pp.578-582
• /
• 2003

We propose a novel structure of wavelength selective optical add/drop module comprising two tap couplers and a fiber Bragg grating. The device has unique features including a simpler structure and a lower cost of implementation as compared with existing devices for the same operation. The module performance has been measured and analyzed experimentally. The implemented prototype module shows good performance with no-crosstalk power penalty in a 155 Mbps per channel wavelength-division-multiplexing transmission system but suffers from a relatively high loss of 3.5 ㏈ and 21 ㏈ for transmitted and dropped channels, respectively. While the dropped channel extinction ratio was more than 25 ㏈, the transmitted channel extinction ratio was more than 35 ㏈.

• Journal of the Optical Society of Korea
• /
• v.4 no.1
• /
• pp.66-70
• /
• 2000

The main problem of image projection on a transmission type holographic screen is color sepa-ration. And it can be overcome by using a long narrow slit type diffuser as a source of the object beam when we record the screen. But that screen is not optimized and so needs changing several conditions. To set up the system many complicate things should be taken into accounted so it is very important to analyze the basic structure by simple concepts and calculations. We designed the system so that recording and projection axis coincide in one line and showed that the analysis of the system is very simple. We did it by a 1st order paraxial approximation calculation and it was good enough to describe the system. The photo-emulsion layer shrinks after processing of the hologram. It induced unsatisfactory color matching at the viewing zone. To overcome this effect, we pre-checked the shrinkage rate of an emulsion layer by experiments and modified the recording set up to compensate for the amount of shrinkage.

• Korean Journal of Optics and Photonics
• /
• v.8 no.3
• /
• pp.250-253
• /
• 1997

The effect of dispersion in optical transmission system changes according to chirp and SPM. Chirp depends on the modulation condition of an external modulator. SPM is proportional to signal power. In this paper, we analyzed the pulse broadening due to SPM and chirp in the system with dispersion by using Split Step Fourier Method and calculated the optimum chirp parameter for 400 km transmission system. Experimental results are presented also.

• Proceedings of the KIEE Conference
• /
• 2003.11c
• /
• pp.823-825
• /
• 2003

A sensor system was designed to measure real time vibro displacement of civil structure. The He-Ne laser is used for the displacement measuring method, because it guarantees short time stabilization, long time output power stability. Also, it guarantees simple maintenances and repairs under actual using condition. The line CCD image sensor(Tcd-142d) is used to detect the displacement of Ne-Ne laser responding to the vibro of civil structure. For accurate measurement and comparison, CDP-50 is used. Usually CDF-50 (Strain type displacement device) is used for the standard correction device of optical measurement equipments. The data processing part is consists of Optical sensor part, Wireless data transmission device, DAQp-1200, and LapView program. The displacement data of vibro from optical sensor part inputted to wireless data transmission device and then transmitted to DAQp-1200 in main control room. DAQp-1200 performs A/D conversion for the receiving data. After that the converted data inputted to computer system using LapView program for user display. The significance of this paper is to develope a convenient, accurate and lost saving real time displacement measurement system for the civil structure.

• Current Optics and Photonics
• /
• v.7 no.4
• /
• pp.362-377
• /
• 2023

Optical information processing technology is characterized by high speed and parallelism, and the light features short wavelength and large information capacity; At the same time, it has various attributes including amplitude, phase, wavelength and polarization, and is a carrier of multi-dimensional information. Therefore, optical encryption is of great significance in the field of information security transmission, and is widely used in the field of image encryption. For multi-image encryption, this paper proposes a multi-image encryption algorithm based on a modified Gerchberg-Saxton algorithm (MGSA) in the Fresnel-transform domain and computational ghost imaging. First, MGSA is used to realize "one code, one key"; Second, phase function superposition and normalization are used to reduce the amount of ciphertext transmission; Finally, computational ghost imaging is used to improve the security of the whole encryption system. This method can encrypt multiple images simultaneously with high efficiency, simple calculation, safety and reliability, and less data transmission. The encryption effect of the method is evaluated by using correlation coefficient and structural similarity, and the effectiveness and security of the method are verified by simulation experiments.

• Journal of the Optical Society of Korea
• /
• v.19 no.5
• /
• pp.437-443
• /
• 2015

In this paper, we analyze the performance of the all-optical multihop radio over a free space optical (RoFSO) communication system with amplify-and-forward (AF) relays under varying weather conditions. The proposed channel model considers the propagation loss, attenuation and atmospheric fading modeled by the Gamma-Gamma (GG) distribution. Both the amplified spontaneous emission (ASE) noise in the all-optical relays and the background noise projected onto receiver apertures have been considered in the analysis. The lower bound analytical expressions for the end-to-end bit error rate (BER) and outage probability are derived for the multihop system employing the all-optical relays with the full channel state information (CSI). Meanwhile, the exact results for BER and outage probability are obtained via Monte Carlo simulation. Results indicate the performance of the proposed system will be improved by the multihop transmission technology. For a fixed number of relays, the BER and outage probability will be increased with the deterioration of the weather conditions.

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