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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 13, Issue 4 - Dec 2009
Volume 13, Issue 3 - Sep 2009
Volume 13, Issue 2 - Jun 2009
Volume 13, Issue 1 - Mar 2009
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Optical Skin-fat Thickness Measurement Using Miniaturized Chip LEDs: A Preliminary Human Study
Ho, Dong-Su ; Kim, Ee-Hwa ; Hwang, In-Duk ; Shin, Kun-Soo ; Oh, Jung-Taek ; Kim, Beop-Min ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 304~309
DOI : 10.3807/JOSK.2009.13.3.304
We tested the feasibility of measuring fat thickness using a miniaturized chip LED sensor module, testing 12 healthy female subjects. The module consisted of a single detector and four sources at four different source-detector distances (SD). A segmental curve-fitting procedure was applied, using an empirical algorithm obtained by Monte-Carlo simulation, and fat thicknesses were estimated. These thicknesses were compared to computed-tomography (CT) results; the correlation coefficient between CT and optical measurements was 0.932 for bicep sites. The mean percentage error between the two measurements was 13.12%. We conclude that fat thickness can be efficiently measured using the simple sensor module.
The Development of Double Clad Fiber and Double Clad Fiber Coupler for Fiber Based Biomedical Imaging Systems
Ryu, Seon-Young ; Choi, Hae-Young ; Ju, Myeong-Jin ; Na, Ji-Hoon ; Choi, Woo-June ; Lee, Byeong-Ha ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 310~315
DOI : 10.3807/JOSK.2009.13.3.310
We report the fabrication of double clad fiber (DCF) and DCF coupler, suitable for fiber based imaging systems requiring the dual-channel transmission. Unlike the conventional DCF which uses silica for both cladding layers, the proposed DCF uses a low-index polymer for its outer-cladding layer coated over the conventional silica inner-cladding layer. The DCF is drawn with a conventional SMF preform but a low-index polymer coating is used for both jacket and outercladding of the fiber. To achieve the cladding mode coupling, a DCF coupler is fabricated by simply twisting two pieces of the proposed DCF after removing the polymer-coating at contacting regions. A cladding mode coupling ratio of 30% was achieved with a contact length of 16 cm. The proposed DCF and DCF coupler were employed in a composite optical coherence tomography (OCT) and fluorescence spectroscopy (FS) system, and both OCT images and FS signal from a plant tissue are measured simultaneously.
Broadband Wavelength-swept Raman Laser for Fourier-domain Mode Locked Swept-source OCT
Lee, Hyung-Seok ; Jung, Eun-Joo ; Jeong, Myung-Yung ; Kim, Chang-Seok ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 316~320
DOI : 10.3807/JOSK.2009.13.3.316
A novel broadband wavelength-swept Raman laser was used to implement Fourier-domain mode locked (FDML) swept-source optical coherence tomography (SS-OCT). Instead of a conventional semiconductor optical amplifier, this study used broadband optical fiber Raman amplification, over 50 nm centered around 1545 nm, using a multi-wavelength optical pumping scheme, which was implemented with the four laser diodes at the center wavelengths of 1425, 1435, 1455 and 1465 nm, respectively, and the maximum operating power of 150 mW each. The operating swept frequency of the laser was determined to 16.7 kHz from the FDML condition of 12 km optical fiber in the ring cavity. The OCT images were obtained using the novel broadband wavelengthswept Raman laser source.
The Advent of Laser Therapies in Dermatology and Urology: Underlying Mechanisms, Recent Trends and Future Directions
Lee, Ho ; Jeong, Yeon-Uk ; Chan, Kin F. ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 321~329
DOI : 10.3807/JOSK.2009.13.3.321
Following their applications in cardiology, ophthalmology and dentistry among others, the advent of lasers in dermatology and urology had become the success story of the past decade. Laser-assisted treatments in dermatology and urology are mainly based on the laser-induced tissue injury/coagulation and/or ablation, depending upon the desirable clinical endpoint. In this review, we discussed the underlying mechanisms of the laser induced tissue ablation. In any medical laser application, the controlled thermal injury and coagulation, and the extent of ablation, if required, are critical. The laser thermal mechanism of injury is intricately related to the selective absorption of light and its exposure duration, similarly to the laser induced ablation. The laser ablation mechanisms were categorized into four different categories (the photo-thermally induced ablation, the photo-mechanically induced ablation, the plasma induced ablation and the photoablation) and their fundamentals are herein described. The brief history of laser treatment modality in dermatology and urology are summarized.
Frequency Swept Laser at 1300 nm Using a Wavelength Scanning Filter Based on a Rotating Slit Disk
Jeon, Man-Sik ; Jung, Un-Sang ; Song, Jae-Won ; Kim, Jee-Hyun ; Oh, Jung-Hwan ; Eom, Jin-Seob ; Kim, Chang-Seok ; Park, Young-Ho ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 330~334
DOI : 10.3807/JOSK.2009.13.3.330
A simple and compact frequency swept laser is demonstrated at
using a wavelength scanning filter based on a rotating slit disk. The laser is comprised of a pigtailed semiconductor optical amplifier, a circulator, and a wavelength scanning filter in an extended cavity configuration. The wavelength scanning filter is composed of a collimator, a diffraction grating, a rotating slit disk, and a mirror. The instantaneous laser output power is more than 5 mW. The scanning range of the laser is extended to 80 nm at the maximum level, and 55 nm in the full width at half maximum at a scanning rate of 2 kHz.
Ultrashort Pulsed Laser Machining for Biomolecule Trapping
Choi, Hae-Woon ; Farson, Dave F. ; Lee, L.James ; Lee, Ho ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 335~340
DOI : 10.3807/JOSK.2009.13.3.335
Ultrashort pulse laser drilling of polycarbonate track-etched membrane (pTEM) material was used to fabricate a mouse embryo cell trapping device. Holes with a diameter of
were fabricated on a
thick membrane using a femtosecond laser with a 150 fs pulse width and 775 nm wavelength and multiple-pulse irradiation. In cell trapping tests, the overall cell occupancy of the machined holes in the fabricated pTEM was found to be more than 80%. The results of a single pulse and multiple pulse irradiation were compared in terms of the surface quality. It was generally found that a single pulse with high energy was less desirable than irradiation with multiple pulses of lower energy.
Scientific and Engineering Applications of Full-field Swept-source Optical Coherence Tomography
Mehta, Dalip Singh ; Anna, Tulsi ; Shakher, Chandra ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 341~348
DOI : 10.3807/JOSK.2009.13.3.341
We report the development of full-field swept-source optical coherence tomography (SS-OCT) in the wavelength range of 815-870 nm using a unique combination of super-luminescent diode (SLD) as broad-band light source and acousto-optic tunable filter (AOTF) as a frequency-scanning device. Some new applications of full-field SS-OCT in forensic sciences and engineering materials have been demonstrated. Results of simultaneous topography and tomography of latent fingerprints, silicon microelectronic circuits and composite materials are presented. The main advantages of the present system are completely non-mechanical scanning, wide-field, compact and low-cost.
In-line Variable Optical Attenuator Based on the Bending of the Tapered Single Mode Fiber
Kim, Kwang-Taek ; Kang, Ji-Hoon ; HwangBo, Seung ; Im, Kie-Gon ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 349~353
DOI : 10.3807/JOSK.2009.13.3.349
We propose a simple in-line variable optical attenuator (VOA) based on the bending effect of tapered single mode fibers. The influence of the taper structure and the reflective index of the external medium surrounding the taper region on the bending loss of the tapered fiber have been investigated experimentally. An attenuation range exceeding 35 dB and a very low excess loss of < 0.2 dB at 1550 nm were achieved. The measured polarization dependent loss of the present VOA at the attenuation level of 10 dB, 20 dB, and 30 dB were 0.1 dB, 0.2 dB, and 0.5 dB, respectively.
Transmission Performance of 40 Gb/s PM Duobinary Signals due to Fiber Nonlinearities in DWDM Systems Using VSB Filtering Techniques
Jang, Ho-Deok ; Kim, Kyoung-Soo ; Lee, Jae-Hoon ; Jeong, Ji-Chai ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 354~360
DOI : 10.3807/JOSK.2009.13.3.354
We investigate theoretically the tolerance of 40 Gbps phase-modulated (PM) duobinary signals using a vestigial sideband (VSB) filter on impairments which occurred in dense wavelength-division multiplexing (DWDM) systems, compared to the conventional duobinary signals. Our simulation results show that PM duobinary signals can't have the gain on the spectral efficiency achieved by utilizing the VSB filtering technique. In order to increase the spectral efficiency, they indispensably require to be transmitted at the optimum bandwidth of multiplexer (MUX) and demultiplexer (DEMUX) since they are susceptible to inter-channel crosstalk. It is also shown that the PM duobinary modulation format has a large tolerance on self-phase modulation (SPM) and cross-phase modulation (XPM) under the condition which MUX and DEMUX have been tuned at an optimum bandwidth; it has 1.2 dB power penalty at the fiber launching power (FLP) of 15 dBm and the channel spacing of 50 GHz.
Performance Analysis for Optimizing Threshold Level Control of a Receiver in Asynchronous 2.5 Gbps/1.2 Gbps Optical Subscriber Network with Inverse Return to Zero(RZ) Coded Downstream and NRZ Upstream Re-modulation
Park, Sang-Jo ; Kim, Bong-Kyu ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 361~366
DOI : 10.3807/JOSK.2009.13.3.361
We propose the performance enhancing method optimization of an asynchronous 2.5 Gbps/1.25 Gbps optical subscriber network with inverse RZ (Return to Zero) coded downstream and NRZ (Non Return to Zero) upstream re-modulation by adjusting threshold level control of a receiver. We theoretically analyze the BER (Bit Error Rate) performance by modeling the occurrence of BER by simulation with MATLAB according to the types of downstream data. The results have shown that the normalized threshold level in an optical receiver could be saturated at 1/3 as the SNR (Signal to Noise Ratio) increases. The needed SNR for obtaining the BER
can be reduced by
5 dB by optimizing the normalized threshold level at 1/3 instead of by using the conventional receiver with threshold level of 0.5. The proposed system can be a useful technology for asynchronous optical access networks with asymmetric upstream and downstream data rates, because the improved minimum receiving power could replace a light source with a source with lower power and lower cost in an OLT (Optical Line Termination).
Non-data Aided Timing Phase Recovery Scheme for Digital Equalization of Chromatic Dispersion and Polarization Mode Dispersion
Park, Jang-Woo ; Chung, Won-Zoo ; Park, Jong-Sun ; Kim, Sung-Chul ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 367~372
DOI : 10.3807/JOSK.2009.13.3.367
In this paper we propose an electronic domain timing phase selection scheme for the optical communication systems suffering from inter-symbol-interference (ISI) distortion due to chromatic dispersion (CD) or polarization mode dispersion (PMD). In the presence of CD/PMD a proper timing phase selection is important for discrete time domain equalizers, since different timing phases produce different nonlinear ISI channels of different severity. The proposed timing phase recovery scheme based on dispersion minimization (DM) practically approximates the optimal minimum mean squared error (MMSE) timing phase without training signals which reduces overall throughput substantially, especially in time-varying channels such as PMD. The simulation results show that the proposed DM timing agrees with MMSE timing phase, under proper normalization of the received signals, for various dispersion and OSNR.
An Analysis of the Delay and Jitter Performance of DBA Schemes for Differentiated Services in EPONs
Choi, Su-Il ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 373~378
DOI : 10.3807/JOSK.2009.13.3.373
An Ethernet passive optical network (EPON) is a low-cost, high-speed solution to the bottleneck problem of a broadband access network. This paper analyzes the delay and the jitter performance of dynamic bandwidth allocation (DBA) schemes for differentiated services in EPONs. Especially, the average packet delay and the delay jitter of the expedited forwarding (EF) traffic class are compared, with consideration as to whether a cyclic or an interleaved polling scheme is superior. This performance evaluation reveals that the cyclic polling based DBA scheme provides constant and predictable average packet delay and improved jitter performance for the EF traffic class without the influence of load variations.
Vergence Control of Binocular Stereoscopic Camera Using Disparity Information
Kwon, Ki-Chul ; Lim, Young-Tae ; Kim, Nam ; Song, Young-Jun ; Choi, Young-Soo ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 379~385
DOI : 10.3807/JOSK.2009.13.3.379
The vergence control of binocular stereoscopic camera is the most essential factor for acquiring high quality stereoscopic images. In this paper, we proposed a binocular stereoscopic camera vergence control method using disparity information by the simple image processing and estimate the quantity of vergence control using the Lagrange interpolation equation. The method of extracting disparity information through image processing is as follows: first the key-object in left & right images was extracted through labeling of the central area of the image, and then a simple method was used for calculating the disparity value of the same key-object in the labeled left and right images. The vergence control method uses disparity information and keeps the convergence distance of left & right cameras and the distance of the key-object the same. According to the proposed method, variance in the distance of the key-object and application of calculated disparity information of obtained left & right images to the quadratic Lagrange interpolation equation could estimate the quantity of vergence control, which confirmed that the method of stereoscopic camera vergence control can be simplified through experiments on various key-objects and other convergence distance.
A PSPICE Circuit Modeling of Strained AlGaInN Laser Diode Based on the Multilevel Rate Equations
Lim, Dong-Wook ; Cho, Hyung-Uk ; Sung, Hyuk-Kee ; Yi, Jong-Chang ; Jhon, Young-Min ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 386~391
DOI : 10.3807/JOSK.2009.13.3.386
PSPICE circuit parameters of the blue laser diodes grown on wurtzite AlGaInN multiple quantum well structures were extracted directly from the three level rate equations. The relevant optical gain parameters were separately calculated from the self-consistent multiband Hamiltonian. The resulting equivalent circuit model for a blue laser diode was schematically presented, and its modulation characteristics, including the pulse response and the frequency response, have been demonstrated by using a conventional PSPICE.
Detection of Avian Influenza-DNA Hybridization Using Wavelength-scanning Surface Plasmon Resonance Biosensor
Kim, Shin-Ae ; Kim, Sung-June ; Lee, Sang-Hun ; Park, Tai-Hyun ; Byun, Kyung-Min ; Kim, Sung-Guk ; Shuler, Michael L. ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 392~397
DOI : 10.3807/JOSK.2009.13.3.392
We designed a wavelength interrogation-based surface plasmon resonance (SPR) biosensor to detect avian influenza DNA (AI-DNA). Hybridization reactions between target AI-DNA probes and capture probes immobilized on a gold surface were monitored quantitatively by measuring the resonance wavelength in the visible waveband. The experimental results were consistent with numerical calculations. Although the SPR detection technique does not require the DNA to be labeled, we also evaluated fluorescently-labeled targets to verify the hybridization behavior of the AI-DNA. Changes in resonance were found to be linearly proportional to the amount of bound analyte. A wavelength interrogation-type SPR biosensor can be used for rapid measurement and high-throughput detection of highly pathogenic AI viruses.
Terahertz Frequency Spreading Filter via One-dimensional Dielectric Multilayer Structures
Yi, Min-Woo ; Kim, Young-Chan ; Yee, Dae-Su ; Ahn, Jae-Wook ;
Journal of the Optical Society of Korea, volume 13, issue 3, 2009, Pages 398~402
DOI : 10.3807/JOSK.2009.13.3.398
We present a method of using one-dimensional dielectric multilayer structures for designing terahertz frequency spreading filters. The interference of terahertz pulses in these structures composed of alternating weak and strong refractive materials allows design of well-separated THz frequency components within a modulation-limited THz spectral envelope. The design characteristics of these coarse THz combs are limited by the saturation effect and also by the deformation of the THz pulse time-traveling within the structure. The details of the designed THz waveform synthesis from these THz multilayer spectral filters are verified by experiments using time-domain terahertz pulsed spectroscopy.