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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Optical Society of Korea
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Journal DOI :
Optical Society of Korea
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Volume & Issues
Volume 7, Issue 4 - Dec 2003
Volume 7, Issue 3 - Sep 2003
Volume 7, Issue 2 - Jun 2003
Volume 7, Issue 1 - Mar 2003
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Statistical Characteristics of Polarization - Sensitive Optical Coherence Tomography for Tissue Imaging
Oh, Jung-Taek ; Kim, Beop-Min ; Kim, Seung-Woo ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 211~215
DOI : 10.3807/JOSK.2003.7.4.211
Statistical characteristics of the backscattered light from turbid tissues obtained by polarizationsensitive optical coherence tomography are investigated. The amplitude of the backscattered light is found to faithfully follow the Rayleigh distribution predicted by the scattering theory of electromagnetic waves in random media. The probability density function of the phase difference between the two orthogonal polarization components of the backscattered light is explicitly derived and then verified in comparison with the experimental data measured from in-vitro tissues of porcine ligament.
Spatial Resolution Enhancement with Fiber - based Spectral Filtering for Optical Coherence Tomography
Choi, Eun-Seo ; Na, Ji-Hoon ; Lee, Byeong-Ha ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 216~223
DOI : 10.3807/JOSK.2003.7.4.216
We report a technique that improves the spatial resolution of optical coherence tomography (OCT) by utilizing fiber-based spectral filtering. The proposed technique improves the resolution by filtering out the erbium’s characteristic peak from the amplified spontaneous emission (ASE) source spectrum, and reshaping the spectrum to Gaussian-like. We used a long period fiber grating (LPG) and an erbium doped fiber (EDF) absorber for the spectral filtering. An in-house made ASE source as well as a commercial ASE source [ASE-FL7002] was used as the OCT sources to study the proposed technique. The resolution of the OCT based on an in-house made ASE source is enhanced from 200 to 40 ㎛ with an LPG. While, the resolution of the OCT based on a commercial ASE source is enhanced from 25 to 19 ㎛ with the aid of an EDF absorber. However, sidelobes still exist in the interferogram due to imperfect spectral filtering, which limited the resolution. Further enhancement in the spatial resolution of the OCT system using the ASE source is possible with the aid of cascaded LPGs and/or carefully designed EDF absorber.
Optical Delay Amplified by Chirped Fiber Bragg Gratings
Lee, Byeong-Ha ; Mudhana, Gopinath ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 224~229
DOI : 10.3807/JOSK.2003.7.4.224
We report a novel optical delay line that can be implemented using only optical fiber and fiber devices without the need for any bulk-optic devices such as lens, prism, and moving mirror. The dispersive property of a chirped fiber Bragg grating (CFBG) is exploited to get the delay. The proposed delay line constitutes two identical CFBGs cascaded in the reverse order with one of them being strained. Analysis reveals that the small displacement or the strain applied on the CFBG is effectively amplified in the delay line by the ratio of the minimum resonant wavelength and the reflection bandwidth of the CFBG. The dispersion properties of the CFBG with and without the strain are analyzed in detail. The theoretical performance of the proposed delay line is also discussed. Applications of the proposed delay line are expected in the field of high-speed optical coherence tomograpy.
Conceptual Design of Soft X-ray Microscopy for Live Biological Samples
Kim, Kyong-Woo ; Nam, Ki-Yong ; Kwon, Young-Man ; Shim, Seong-Taek ; Kim, Kyu-Gyeom ; Yoon, Kwon-Ha ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 230~233
DOI : 10.3807/JOSK.2003.7.4.230
This study describes the conceptual design of a soft x-ray microscope system based on a laserbased source for biomedical application with high resolution (
50nm). The laboratory scale soft x-ray microscope consists of high power laser plasma x-ray source and grazing incidence mirrors with high reflectivity. The laser plasma source used for developing this system employs Q-switched Nd-YAG pulsed laser. The laser beam is focused on a tantalum (Ta) target. The Wolter type I mirror was used as condenser optics for sample illumination and as objective mirror for focusing on a detector. The fabrication of the Wolter type I mirror was direct internal cutting using ultraprecision DTM. A hydrated biological specimen was put between the two silicon wafers, the center of which was
windows of 100㎚ thickness. The main issues in the future development work are to make a stable, reliable and reproducible x-ray microscope system.
Polarization Spectral Imaging System for Quantitative Evaluation of Port Wine Stain Blanching Following Laser Treatment
Jung, Byung-Jo ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 234~239
DOI : 10.3807/JOSK.2003.7.4.234
Objective methods to assess quantitatively port wine stain (PWS) blanching in response to laser therapy are needed to improve laser therapeutic outcome. Previous studies have attempted to assess objectively PWS color based on point measurement devices. To date, these approaches have typically been limited by a number of factors such as small test area and need for contact. To address these issues, a polarization spectral imaging system and an image analysis method have been developed to evaluate quantitatively erythema and melanin content distribution in skin. The developed polarization spectral imaging system minimizes artifacts such as glaring, shadowing, and non-uniform illumination that interfere with image fidelity. Furthermore, the image analysis method has been employed to get images of skin melanin and erythema indices from the acquired color images for quantitative analysis. Finally, using PWS patient color image, the effectiveness in laser treatment of PWS was evaluated by calculating relative erythema index image that is the relative erythema index of PWS region to the normal region. The developed device and analysis method appears to be a simple and effective method for quantitative analysis of PWS blanching.
Reagentless Determination of Human Serum Components Using Infrared Absorption Spectroscopy
Hahn, Sang-Joon ; Yoon, Gil-Won ; Kim Gun-Shik ; Park Seung-Han ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 240~244
DOI : 10.3807/JOSK.2003.7.4.240
Simultaneous determination of concentrations for four major components in human blood serum was investigated using a Fourier-transform mid-infrared spectroscopy. Infrared spectra of human blood serum were measured in 8.404 ∼ 10.25
range where the highest absorption peaks of glucose are located. A partial least square (PLS) algorithm was utilized to establish a calibration model for determining total protein, albumin, globulin and glucose levels which are commonly measured metabolites. The standard error of cross validation obtained from our multivariate calibration model was 0.24 g/dL for total protein, 0.15 g/dL for albumin, 0.17 g/dL for globulin, and 6.68 mg/dL for glucose, which are comparable with or meet the criteria for clinical use. The results indicate that the infrared absorption spectroscopy can be used to predict the concentrations of clinically important metabolites without going through a chemical process with a reagent.
Study of Propagation of Light along an Acupuncture Meridian
Choi, Chun-Ho ; Soh, Kwang-Sup ; Lee, Sang-Min ; Yoon Gil-Won ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 245~248
DOI : 10.3807/JOSK.2003.7.4.245
Propagation of light along a pericardium meridian is measured and compared with that along a non-meridian path one cm away from the meridian. Source-light is illuminated on the Nei-Guan(PC6) and propagated light is detected at three points along the meridian. Four reference points are one cm away from the corresponding meridian points, respectively. Light propagates better along the meridian than the reference path with more than twenty percent difference for all the subjects tested.
Multi - channel Spectrum Analyzer for High Capacity Optical Transport Networks
Youn, Ji-Wook ; Kim, Hyung-Joo ; Lee, Jong-Hyun ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 249~252
DOI : 10.3807/JOSK.2003.7.4.249
A simple multi-channel spectrum analyzer using an InGaAs array sensor and a diffraction grating is proposed and developed for high-capacity optical transport networks. With the developed multichannel spectrum analyzer, we could measure signal power, wavelength, and optical signal-to-noise ratio of each channel for multi-channel optical signals with 100 GHz and 50 GHz channel spacing, simultaneously. We could measure each channel power and wavelength with a deviation of less than 0.2 dB and 0.063 nm, respectively. We have obtained optical signal-to-noise ratio with a deviation of less than 1.0 dB compared with conventional optical spectrum analyzer in the wide input power range between -42 dBm and -27 dBm per channel.
Waveguide Digital Optical Switches
Kim Seung-Jae ; Jung, Hong-Sik ; Lee, Han-Young ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 253~257
DOI : 10.3807/JOSK.2003.7.4.253
We propose and demonstrate a novel polarization- and wavelength-independent digital electrooptic switch in
with switching voltage of
integrated optic switch is characterized by a step-like response to the applied voltage. Switching is achieved through adiabatic mode evolution in an asymmetric waveguide junction. An average insertion loss of ∼4.5dB and polarization independent switching with average crosstalk of -12dB are achieved.
Modeling and Optimization of RMS Pulse Width for Transmission in Dispersive Nonlinear Fibers
Lee, Jong-Hyung ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 258~263
DOI : 10.3807/JOSK.2003.7.4.258
Simple algebraic expressions are derived to approximate the optimal input RMS pulse width and the resulting output RMS pulse width in single-mode fibers. The results are compared with the previously published methods and with numerical results by the split-step Fourier method. In addition, for a transform-limited Gaussian input pulse, it is shown that there is no optimum input pulse width to minimize the output spectrum width. Finally, with fiber nonlinearity, it is shown mathematically that there is not an optimum input pulse width to minimize the product,
, which is inversely proportional to the transmission capacity of WDM systems.
A Hybrid Algorithm to Reduce the Computation Time of Genetic Algorithm for Designing Binary Phase Holograms
Nguyen, The-Anh ; An, Jun-Won ; Choi, Jae-Kwang ; Kim, Nam ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 264~268
DOI : 10.3807/JOSK.2003.7.4.264
A new approach to design binary phase holograms, with less computation time and equal effi-ciency compared with the genetic algorithm method, is proposed. Synthesized holograms having diffraction efficiency of 75.8% and uniformity of 5.8% are tested in computer simulation and experimentally demonstrated.
Gaussian Apodization Technique in Holographic Demultiplexer Based on Photopolymer
Do, Duc-Dung ; An, Jun-Won ; Kim, Nam ; Lee, Kwon-Yeon ;
Journal of the Optical Society of Korea, volume 7, issue 4, 2003, Pages 269~274
DOI : 10.3807/JOSK.2003.7.4.269
In this paper, a Gaussian apodization technique applied to a transmission volume hologram for holographic demultiplexer is proposed. The Gaussian apodized grating of 15 mm
thickness and 3.2 mm horizontal standard deviation of the Gaussian index modulation profile was fabricated. A 22-channel demultiplexer based on that grating has been optically demonstrated. The channel spacing, the interchannel cross-talk level and the channel uniformity of 0.8 nm, -30 dB and 1.5 dB, respectively, were obtained.