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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 16, Issue 6 - Dec 2005
Volume 16, Issue 5 - Oct 2005
Volume 16, Issue 4 - Aug 2005
Volume 16, Issue 3 - Jun 2005
Volume 16, Issue 2 - Feb 2005
Volume 16, Issue 1 - Feb 2005
Selecting the target year
Bouble Resonance Optical Pumping in the Transition 5S
of Rb Atoms
Moon, H.S. ; Lee, L. ; Kim, J.B. ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 297~303
DOI : 10.3807/KJOP.2005.16.4.297
We present the double resonance optical pumping(DROP) spectra according to the laser power, the polarization combination of lasers, and the alignment of lasers in the transition
We observed obviously changing DROP spectrum according to the laser power in the transition
involved the cycling transition. The laser power effects are attributed to the low optical-pumping-effect in the cycling transition. We observed changing DROP spectrum depending on the polarizations of the lasers. The laser polarization effects are attributed to the changing transition probability according to the polarizations of lasers. We compared the co-propagation with the counter-propagation and the spectral linewidths were 12.2 MHz and 6.9 MHz, respectively.
Studies on Curved Diffractive Optical Elements in EUV
Choi, Sung-Eul ; Lee, Yong-Woo ; Kwon, Myung-Hoi ; Kim, Yong-Hoo ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 304~312
DOI : 10.3807/KJOP.2005.16.4.304
Field performance of several different types of diffractive optical elements(DOEs) has been carried out. Using Zemax model, we have designed five different types of DOEs, such as transmissive flat-DOE, transmissive curved-DOE, reflective flat-DOE, reflective curved-DOE and parabolic mirror, We have applied two different wavelengths, i.e., 13 m(EUV) and 632.8 nm(visible) to above DOEs. Off_axis dominate aberrations and the diffraction limiting (Rayleigh limit) field angles have been investigated and compared at both wavelengths for each DOE. At diffraction limit, field angle of curved-DOEs was much greater than that of flat-DOEs for both transmission and reflective types. We also showed that dominated off_axis aberration of flat-DOEs was coma, but that of curved-DOEs was mixture of astigmatism and curvature of field. The measured field angle and expected OPD aberrations were well coincided with theoretical ones. Increasing the ratio of field angle with wavelength was more effective in curved-DOEs than flat-DOEs.
Eye Pattern Characteristic Based Active Stabilization Method for Direct Delection Receiver in Differential Phase Shift Key System
Jang, Youn-Seon ; Park, Heuk ; Kim, Kwang-Joon ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 313~318
DOI : 10.3807/KJOP.2005.16.4.313
We propose an active stabilization method for the receiver of NRZ-DPSK transmission. The 1-bit delayed Mach-Zehlder interferometer is thermally controlled to maintain the largest DC component power ratio between the constructive and destructive output ports, for the optimum transmission condition. This method is very cost effective since no additional components are required. Experimental results show that the proposed scheme guarantees error free performance even when there was ~ 1 GHz optical carrier frequency fluctuation in 10 Gbps transmission.
Detection of White Light Interference Peak Position utilizing Analog Signal Processing
Yeh, Yun-Hae ; Lee, Jong-Kwon ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 319~325
DOI : 10.3807/KJOP.2005.16.4.319
A signal processing method for white light interferometry (WLI), which performs a series of analog signal processing steps to locate the central interference fringe position at high speed: is developed and applied to a WLI temperature sensor system. We found that the new method has random walk of
with good linearity. However, the temperature change in the path-matching interferometer results in drift of the measured sensor output. The temperature dependence of drift in the WLI temperature sensor system, was calculated to be
. It is also found that the relationship between the peak spacing in the interferogram and the spacing measured by the method can be nonlinear when the fringe spacing is comparable to the coherence length of the source.
Single Path Phase-only Security System using Phase-encoded XOR Operations in Fourier Plane
Shin, Chang-Mok ; Cho, Kyu-Bo ; Kim, Soo-Joong ; Noh, Duck-Soo ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 326~333
DOI : 10.3807/KJOP.2005.16.4.326
Phase-only encryption scheme using exclusive-OR rules in Fourier plane and a single path decryption system are presented. A zero-padded original image, multiplied by a random phase image, is Fourier transformed and its real-valued data is encrypted with key data by using XOR rules. A decryption is simply performed based on 2-1 setup with spatial filter by Fourier transform for multiplying phase-only encrypted data by phase-only key data, which are obtained by phase-encoding process, and spatial filtering for zero-order elimination in inverse-Fourier plane. Since the encryption process is peformed in Fourier plane, proposed encryption scheme is more tolerant to loss of key information by scratching or cutting than previous XOR encryption method in space domain. Compare with previous phase-visualization systems, due to the simple architecture without a reference wave, our system is basically robust to mechanical vibrations and fluctuations. Numerical simulations have confirmed the proposed technique as high-level encryption and simple decryption architecture.
Design of Multi-phase Holographic Optical Low-pass Filter for the Improvement of the MTF Characteristics
Oh, Yong-Ho ; Go, Chun-Soo ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 334~339
DOI : 10.3807/KJOP.2005.16.4.334
We studied the spatial filtering characteristics of a multi-phase hologram optical low-pass filter(HOLF). Using the Monte-Carlo based hologram generation program, we designed holograms whose diffraction patterns are circular shaped 21 beams and calculated the diffraction efficiencies and MTFs. 4-phase HOLF have the same diffraction efficiency as that of 2-phase HOLF. The MTF graphs of the two are also nearly alike. But 8-phase HOLF shows higher efficiency than those previously discussed and has larger MTF values in the low frequency region. 16-phase HOLF has just a little better characteristics than 8-phase. Considering the errors which can arise in the process of making holograms, 8-phase HOLF fits the goal of improving the resolution of spatial filter. We also fabricated 8-phase HOLF and .measured MTF The experimental results agree well with the theoretical expectations.
Ge-doped Boro-Phospho-Silicate Glass Micro-lens Array Produced by Thermal Reflow
Jeong, Jin-ho ; Oh, Jin-Gyeong ; Choi, Jun-Seok ; Choi, Gi-Seon ; Lee, Hyeong-Jong ; Bae, Byeong-Seong ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 340~344
DOI : 10.3807/KJOP.2005.16.4.340
Microlens cells of Ge-doped BPSG (Boro-Phospho-Silicate Glass) are fabricated by dicing the film produced by FHD (Flame Hydrolysis Deposition). Microlens arrays of
square unit are produced by the thermal reflow of the diced unit cells at
. The gap between the microlenses was about
and the thickness of the produced lens was about
. We analyzed the reflowed shape of the microlens cell by an image-process technique, and the focal length was about
. This method of fabricating a microlens is simple and inexpensive compared to the conventional method using the photolithographic process. Also, the control of the radius of curvature of the microlens is easier and a more precise microlens way of various types can be fabricated using this method.
Low-Cost Hologram Module for Optical Pickup by Adjusting Photodiode Package
Jeong, Ho-Seop ; Kyong, Chon-Su ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 345~353
DOI : 10.3807/KJOP.2005.16.4.345
We proposed a new and cost-effective method fer assembling holographic pickup modules without any high resolution vision system. Assembling was accomplished by adjusting photodiode package only, leading to a low cost, holographic pickup module. Focus and tracking error signals were simply determined by comparing spot sizes and by using the 3 beam method, respectively, based on four-sectional holographic optical elements. In experiment, we assembled a hologram module and estimated performance of the proposed method fur a holographic pickup module used in compact disc system.
Advanced LWIR Thermal Imaging System with a Large Zoom Optics
Hong, Seok-Min ; Kim, Hyun-Sook ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 354~360
DOI : 10.3807/KJOP.2005.16.4.354
A high performance LWIR(long wavelength infra red) zoom thermal imaging sensor using
HgCdTe(MCT) linear detector has been developed by ADD Korea. The optical system consists of zoom telescope having large objective about 190 mm diameter and optically well corrected scanning system. The zoom ratio of the telescope is 3: 1 and its magnification change is performed by moving two lens groups. And also these moving groups are used for athermalization of the system. It is certain that the zoom sensor can be used in wide operating temperature range without any degradation of the system performance. Especially, the sensor image can be displayed with the HDTV(high definition television) format of which aspect ratio is 16:9. In case of HDTV format, the scanning system is able to display 620,000 pixels. This function can make wider horizontal field of view without any loss of performance than the normal TV format image. The MRTD(minimum resolvable temperature difference) of the LWIR thermal imaging sensor shows good results below 0.04 K at spatial frequency 2 cycles/mrad and 0.23 K at spatial frequency 8 cycles/mrad at the narrow field of view.
Multiple-Point-Diffraction Interferometer : Error Analysis and Calibration
Kim, Byoung-Chang ; Kim, Seung-Woo ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 361~365
DOI : 10.3807/KJOP.2005.16.4.361
An absolute interferometer system with multiple point-sources is devised for tile 3-D measurement of rough surface profiles. The positions of the point sources are determined to be the system parameters that influence the measurement accuracy, so they are calibrated precisely prior to performing actual measurements. For the calibration, a CCD camera composed of a two-dimensional array of photo-detectors was used. Performing optimization of the cost function constructed with phase values measured at each pixel on the CCD camera, the position coordinates of each point source is precisely determined. Measurement results after calibration performed for the warpage inspection of chip scale packages (CSPs) demonstrate that the maximum discrepancy is 9.8 mm with a standard deviation o( 1.5 mm in comparison with the test results obtained by using a Form Taly Surf instrument.
A study on the fabrication of periodically poled Ti:LiNbO
(PPLN) by the control of charge
Kim, Won-Joung ; Jung, Hong-Sik ; Lee, Han-Young ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 366~375
DOI : 10.3807/KJOP.2005.16.4.366
A fabrication process of periodic electric field assisted poling of Ti-diffused channel waveguides in LiNbO3 (Ti:PPLN) has been developed and improved using a periodic 180o phase inversion along the z-axis. The zig for poling inversion and the Labview program of charge control have been devised. Pulse high voltage and duty cycle were adjusted based on the estimated charge required for poling inversion. Monitoring the change of leakage current under applied voltage less than the coercive voltage also minimized a breakdown.
A Study on Ti:LiNbO
Integrated Optical Wavelength Tunable Polarization Mode Controllers
Moon, Je-Young ; Jung, Hong-Sik ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 376~383
DOI : 10.3807/KJOP.2005.16.4.376
We designed and fabricated integrated-optic tunable polarization controllers based on
with the Ti-indiffused waveguide along the y-axis utilizing the electro-optic effect. The device consists of
mode converters and TE/TM phase shifters. We analyzed the operation principles of each device utilizing transfer matrices based on a Jones matrix and simulated shifting of the center wavelength by inducing voltage. We confirmed experimentally that the fabricated devices control the tunability of the center wavelength and the input SOP.
Polymer Optical Microring Resonator Using Nanoimprint Technique
Kim, Do-Hwan ; Im, Jung-Gyu ; Lee, Sang-Shin ; Ahn, Seh-Won ; Lee, Ki-Dong ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 384~391
DOI : 10.3807/KJOP.2005.16.4.384
A polymer optical microring resonator, which is laterally coupled to a straight bus waveguide, has been proposed and demonstrated using a nanoimprint technique. The propagation loss of the ring waveguide and the optical power coupling between the ring and bus waveguides was calculated by using a beam propagation method, then the dependence of the device performance on them was investigated using a transfer matrix method. We have especially introduced an imprint stamp incorporating a smoothing buffer layer made of a silicon nitride thin film. This layer played an efficient role in improving the sidewall roughness of the waveguide pattern engraved on the stamp and thus reducing the scattering loss. As a result the overall Q factor of the resonator was greatly increased. Also it reduced the gap between the ring and bus waveguides effectively to enhance the coupling between them, without relying on the direct writing method based on an e-beam writer. As for the achieved device performance at the wavelength of 1550 nm, the quality factor, the extinction ratio, and the free spectral range were ~103800, ~11 dB, and 1.16 m, respectively.
Development of 2.5 Gbps Multi-Channel Tunable Wavelength Converter Based on Cross Gain Modulation in Semiconductor Optical Amplifier
Son, Jung-Min ; Lee, Sang-Sun ;
Korean Journal of Optics and Photonics, volume 16, issue 4, 2005, Pages 392~396
DOI : 10.3807/KJOP.2005.16.4.392
A new structure of tunable wavelength converter based on XCM in SOA was tried and analyzed. This converter used single SOA and had very simple structure. In this paper, results were experimentally obtained and demonstrated. Pump signal was generated with NRZ
and data rate 2.5 Gbps. WDM multi conveted signals showed more than 8.3 dB extinction ratio. For BER performance, all these converted signals had within 5.0 dB power penalty compared with the pump signal. With these results, we showed that this converter was suitable for 2.5 Gbps WDM multi-channel wavelength converting.