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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Optics and Photonics
Journal Basic Information
Journal DOI :
Optical Society of Korea
Editor in Chief :
Volume & Issues
Volume 22, Issue 6 - Dec 2011
Volume 22, Issue 5 - Oct 2011
Volume 22, Issue 4 - Aug 2011
Volume 22, Issue 3 - Jun 2011
Volume 22, Issue 2 - Apr 2011
Volume 22, Issue 1 - Feb 2011
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Long-Period Fiber Gratings Based on Periodically Surface-Etched Structure Imprinted by Using a Photoresist Polymer
Park, Sang-Oh ; Kwon, Oh-Jang ; Han, Young-Geun ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 1~4
DOI : 10.3807/KJOP.2011.22.1.001
A new fabrication technique of long-period fiber gratings with periodically surface-etched structures is proposed. Transmission characteristics of the periodically surface-etched long-period fiber gratings are improved by changing strain because of variation of coupling strength between the core and the cladding modes. The sensitivities of the periodically surface-etched long-period fiber gratings to strain, torsion, and ambient refractive index were measured. The strain and the torsion sensitivities were measured to be
and -1.30 nm m/rad, respectively. The ambient index sensitivity was measured to be -31.33 nm/RIU from a range from 1.33 to 1.42.
Measurement of Numerical Aperture of Graded-index Plastic Optical Fiber by Using a Variable Aperture
Kim, Dae-Kyu ; Kim, Bo-Ram ; Lee, Byoung-Hwak ; Park, Seung-Han ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 5~9
DOI : 10.3807/KJOP.2011.22.1.005
There are technical difficulties in measuring the numerical apertures of multi-mode gradient-index plastic optical fibers (GI-POFs) due to their strong speckle noise originating from dopants, non-uniformity of gradient-index profile, and multi-mode interference. Therefore, we propose a new method of obtaining the numerical aperture by controlling the size of the incident laser beam and measuring the numerical aperture of GI-POF. The results show that we can get a value for the numerical aperture of GI-POF very similar to that measured by the conventional method. We can also obtain the optimum launching condition of input beam and maximum coupling efficiency.
Auto-focus of Optical Scanning Holographic Microscopy Using Partial Region Analysis
Kim, You-Seok ; Kim, Tae-Geun ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 10~15
DOI : 10.3807/KJOP.2011.22.1.010
In this paper, we propose an auto-focusing algorithm which extracts a depth parameter by analyzing a selected part of a hologram, and we use experimental results to show that the algorithm is practical. First, we record a complex hologram using Optical Scanning Holography. Next we select some part of hologram and extract depth information through Gaussian low pass filtering, synthesizing a real-only hologram, power fringe-adjusted filtering and inverting to a new frequency axis. Finally, we reconstruct the hologram automatically using the extracted depth location.
Modulation Transfer Function System for a Mid-infrared Lens by Knife-edge Scanning Technique
Song, Se-Yong ; Jo, Jae-Heung ; Hong, Sung-Mok ; Lee, Hoi-Youn ; Lee, Yun-Woo ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 16~22
DOI : 10.3807/KJOP.2011.22.1.016
We fabricate a measuring system to measure the modulation transfer function (MTF) of a mid-infrared imaging silicon lens by using the knife-edge scanning technique. In particular, we measure on-axial tangential MTF of the silicon lens with the focal length of 50 mm and F-number F/4 in the wavelength band of mid-infrared between
. In order to obtain the infinite object, the off-axial parabolic reflector with the focal length of 2.545 m is utilized. In the comparison with measured MTF data and designed MTF values curve, we find that the tolerance of measured MTF data below the spatial frequency of 7 lp/mm is within 2%.
Reflective Bistable Chiral Splay Nematic Liquid Crystal Display
Kim, Tae-Hyung ; Lee, Joong-Ha ; Shen, Zheng-Guo ; Jang, Ji-Hyang ; Kim, Jeong-Soo ; Jhun, Chul-Gyu ; Kwon, Soon-Bum ; Yoon, Tae-Hoon ; Kim, Jae-Chang ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 23~29
DOI : 10.3807/KJOP.2011.22.1.023
Bistable chiral splay nematic liquid crystal display (BCSN LCD) is a memory type liquid crystal display using splay and
twist states as two stable states. When the cell thickness to pitch (d/p) ratio is 0.25, splay and
twist states have permanent memory time. However, when the transition from
twist state to splay state is caused by a fringe field, pixel regions show that the splay state is not perfect, but rather includes a contribution from the
twist state. In this paper, we propose a reflective BCSN LCD using
twist state in which the two stable states do not coexist. The fabricated reflective BCSN LC cell shows a high contrast ratio of over 30:1 and response times of 950 ms and 450 ms in vertical and fringe field switching, respectively. The proposed cell also shows wide viewing angle characteristics of
in left- and right directions.
Automatic Alignment of a Collimating Mirror by Using Phase Image Correlatio
Kim, Hyun-Suk ; Tserendolgor, D. ; Kim, Dae-Suk ; Lee, Hyung-Chul ; Kim, Soo-Hyun ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 30~34
DOI : 10.3807/KJOP.2011.22.1.030
A novel alignment method that can be used for aligning the collimating mirror employed in a monochromator is described. In most of the spectrometer industry, the alignment of optical components such as a focusing mirror, a grating and a collimating mirror has been performed manually so far. In this paper, we use a matchedfilter based image correlation technique for measuring the accurate image position which is used for aligning the collimating mirror. The experimental results show that with the proposed scheme automatic alignment can be completed within 10 seconds.
PSPICE Modeling and Characterization of Optical Transmitter with 1550 nm InGaAsP LDs
Goo, Yu-Rim ; Kim, Jong-Dae ; Yi, Jong-Chang ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 35~39
DOI : 10.3807/KJOP.2011.22.1.035
The PSPICE equivalent circuit elements of a 1550 nm InGaAsP laser diode were derived by using multi-level rate equations. The device parameters were extracted by using a self-consistent numerical method for the optical gain properties of the MQW active regions. The resulting equivalent circuit model is also applied to an actual optical transmitter, and its PSPICE simulation results show good agreement with the measured results once the parasitic capacitance due to the packaging is taken into account.
Design and Fabrication of Triple-coupler Ring Resonator Filter
Lee, Young-Sik ; Chung, Young-Chul ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 40~45
DOI : 10.3807/KJOP.2011.22.1.040
Design and fabrication of a TCRR (Triple-coupler Ring Resonator) filter which can provide a doubled FSR (Free Spectral Range) compared with a conventional DCRR (Double-coupler Ring Resonator) filter, are discussed. Through the use of a polymer material with a good thermo-optic property and with high contrast between core and cladding polymer, a compact TCRR filter composed of straight and curved buried waveguides of small radius is designed and fabricated. The transmission characteristics from the through and drop ports are measured using a tunable laser and a fiber array block, and the FSR is observed to be 4.4 nm, about twice that of DCRR filter, and almost the same as that obtained from the analysis using a transfer matrix method.
The Development of Confocal Microscopy Using the Amplified Double-compound Flexure Guide
Lee, Sang-Won ; Kim, Wi-Han ; Jung, Young-Dae ; Park, Min-Kyu ; Kim, Jee-Hyun ; Lee, Sang-In ; Lee, Ho ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 46~52
DOI : 10.3807/KJOP.2011.22.1.046
A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.
A Study of the Upper Layer for Improvement of the Extraction Efficiency in LED
Choi, Chul-Hyun ; Lee, Dong-Jin ; Yim, Hae-Dong ; Kim, Bo-Soon ; Sung, Jun-Ho ; Lee, Min-Woo ; O, Beom-Hoan ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 53~57
DOI : 10.3807/KJOP.2011.22.1.053
In this paper, we improved the light extraction efficiency by considering an additional upper layer on the top surface of a conventional LED. We simulated the LED's light emission as functions of the thickness and the refractive index of the upper layer, and analyzed how the condition improved the light efficiency. When the refractive index's range was from 1.05 to 1.40, the LED emission increased. For that case, the emission also increased as the thickness increased. We experimentally showed that the light extraction efficiency was improved about 22% by forming the upper layer on the top surface of an LED using material with refractive index 1.30 at 589.3 nm. It is expected that forming the upper layer on an LED can easily improve the extraction efficiency.
The Measurement and Application of the Minimum Detectable Irradiance for the Infrared Point Source Detection System
Kim, Hyun-Sook ; Yang, Yu-Kyung ; Park, Yong-Chan ;
Korean Journal of Optics and Photonics, volume 22, issue 1, 2011, Pages 58~63
DOI : 10.3807/KJOP.2011.22.1.058
A procedure and method for the MDI(Minimum Detectable Irradiance) measurement of an infrared point source detection system is described in detail and its experimental result is analyzed. The proposed measurement method for MDI can be realized with a collimator in the laboratory environment. In addition, an estimation method of the maximum detection range of the infrared point source detection system is introduced and its performed result is shown.