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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 10, Issue 6 - Dec 1999
Volume 10, Issue 5 - Oct 1999
Volume 10, Issue 4 - Aug 1999
Volume 10, Issue 3 - Jun 1999
Volume 10, Issue 2 - Apr 1999
Volume 10, Issue 1 - Feb 1999
Selecting the target year
Measurement of optical coefficients of multiple scattering media by using frequency domain spectroscopy
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 357~363
A frequency domain spectroscopic system was constructed to investigate the optical properties of multiple scattering media. The alternating current (AC) and phase lag components of backscattered light were measured by using the heterodyne detection method. Absorption and transport scattering coefficients were computed from the values based on diffusion theory. Predictions showed excellent matches in comparison with actual values of absorption and scattering. Predictable ranges of the optical coefficients were analyzed in terms of the distance between light source and detector, and modulation frequencies. A proposed compact experimental set-up using laser diodes can be utilized to estimate non-invasively the optical properties of multiple scattering media such as biological tissues.
Laser scanning unit with plastic f
lenses featuring high resolution
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 364~368
We investigate the evaluation items of LSU (Laser Scanning Unit), such as beam size, f
characteristics, linearity, skew and bow, optical power ratio between image height of 0mm and
108 mm, pitch error, Jitter and shift of printing position. Through the measurement of LSU using BSH (Beam Scan Head) installed on LMC (Linear Motion Controller) which moves linearly within the whole scanning range (-108 mm~+108 mm), we can ascertain plastic f
lenses, which are manufactured by TVLP (Two-step Variable Low Pressure) molding method, to satisfy 600DPI(Dots Per Inch) performance.
The study of property on the michelson interferometric microscopy
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 369~372
We have constructed an interferometric microscopy using a Michelson interferometer and a He-Ne laser. The three dimensional image was obtained by the interference from the reflected signal by a sample surface and from the reflected signal by a mirror. The axial resolution obtained by Michelson interferometric microscopy is as good as that of the white-light interferometer, but the same fringe is obtained when optical path difference is half-wavelength. The image from Michelson interferometric microscopy was compared with the images from the various types of confocal microscopy.
Thin film thickness profile measurement using white light scanning interferometry
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 373~378
White light scanning interferometry is increasingly used for precision profile metrology of engineering surfaces, but its current application is primarily limited to opaque surfaces with relatively simple optical reflection behaviors. In this paper, a new attempt is made to extend the interferometric method to the thickness profile measurement of transparent thin film layers. An extensive frequency domain analysis of multiple reflection is performed to allow both the top and bottom interfaces of a thin film layer to be measured independently at the same time using nonlinear least squares technique. This rigorous approach provides not only point-by-point thickness probing but also complete volumetric film profiles digitized in three dimensions.
Optimization of resolution and color reproduction for color CRT monitor by control of contrast and brightness levels
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 379~385
The characteristics of image quality of a color CRT (cathode ray tube) monitor are studied by changing the contrast and brightness levels. The resolution is assessed by SQRI (square root integral) measured at 9 different combinations of the contrast and brightness levels. The chromaticity coordinates and luminances of red-green-blue channels as a function of the digital value are measured at these combinations and the relationships among the constant-channel chromaticity, color gamut, maximum luminance of a white point with the channel independence are analyzed. From the results, the optimized combination of levels is obtained.
Characteristics of Polarization hologram in a side-chain polymalonic ester
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 386~390
Erasable polarization holographic grating was recorded with two-wave mixing in PCN which was side-chain liquid crystalline polymalonic esters containing two symmetrical 4-cyanoazobenzene as photoresponsive groups. The diffraction efficiency of recorded grating was measured and the characteristics of recording, decay in a dark room and erasing by circularly polarized light were investigated. As the results, birefringence,
n of PCN was measured
, which was 0~100 times higher than those of crystals such as Fe:
crystals. Dark decay rates was
%/hour, which showed the possibility of application as data storage media.
Diffractive characteristics of the photorefractive gratings in
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 391~395
We present the measurement of the diffraction efficiency and response time of the photorefractive grating recorded in
photorefractive crystal doped with 4%-mole MgO. Two laser sources were used in the experiments; frequency-doubled Q-switched Nd:YAG laser (
=532 nm) and cw Ar-ion laser (
=514.5 nm). The same optical geometry was also used in both experiments in order to maintain the experimental consistency. Using the two-wave mixing scheme in both experiments we measured the maximum diffraction efficiency in the range of beam intensity of 1.6~100 W/
, and the response times for both cases of recording and erasing. Two sets of results obtained from the experiments are compared and analyzed.
Subtraction of excess noise in a gyroscope employing a high-power erbium-doped fiber source
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 396~400
In the fiber-optic gyroscope employing a high-power erbium-doped fiber source, the source excess noise was subtracted from the gyro output through a single processing to improve the gyroscope sensitivity. As the result, we obtained the reduction of noise by 13.5 dB (electrical) which was measured from the noise floor spectrum when the gyro was modulated with the depth of 1.8 rad. In addition, the random walk coefficient of the gyro output was reduced by a factor of 4~5.
Design of flat gain EDFAs based on inversion principle and their characteristics
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 401~404
We have developed a direct measurement method for gain coefficients of erbium-doped fiber amplifiers and used the coefficients for the design of flat gain EDFAs. Another simple method of designing EDFAs for WDM was realized as an application of inversion principle.
A Study on the SSF algorithm improvement for the optical propagation simulation
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 405~412
We propose an effective algorithm, which can predict the detailed behavior of the intensity-modulated high speed optical signal after propagating through an optical fiber. The alogrithm is based on the SSF (Split Step Fourier) Method, however, the step size is automatically calibrated in each calculation step to reduce the number of calculations within given round-off error bound. Applying the algorithm to the 2.5 Gbps 100 km transmission and 10 Gbps 40 km transmission simulations, we achieved the calculation time reduction by maximum 1/120 and 1/56 of the calculation time by using the SSF fixed step algorithm previously known. The root-mean-square of the round-off error was kept within -30 dB compared to the signal level throughout the calculation.
Optical filber networks for microwave frequency rejection filters
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 413~418
We report on the frequency response of microwave signal processing networks using optical fiber circuits. Microwave frequency rejection filters using Mach-Zehnder interferometer and Fabry-Perot interferometer are modelled theoretically and tested experimentally. Graphical representation method provides a simple tool for computating single mode fiber delay-line microwave filters. The calculated results are in good agreement with experimental results. A 36dB microwave frequency rejection filter is also demonstrated.
Fabrication and optical properties measurement of the optical filters utilizing fiber-to-planar waveguide coupler
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 419~423
Optical filters utilizing the evanescent filed coupling between the side polished fiber and polymer planar waveguide were fabricated and optical properties of the devices were measured. A scheme for reducing polarization dependent properties of the device was proposed and demonstrated experimentally. Our measurement results showed that resonance wavelengths and filtering depth of the optical filters can be determined by adjusting thickness of planar waveguide and polishing depth of the fiber. The device fabrication procedure including fiber polishing steps and formation of polymer planar waveguide were described. The optical characteristics of fabricated optical filers were that 3 dB bandwidth was 15 nm, the resonance wavelength difference between the TE and TM polarized response was less then 2 nm, and insertion loss was less then 0.2 dB. The measured resonance wavelength drift dut to the variation of ambient temperature was -0.35 nm/
Three-staged amplifier properties of single-short pulsed distributed feedback dye laser using a XeCl laser
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 424~429
The amplifier properties of single distributed feedback dye laser with 106 ps pulse width and 616 nm wavelength were invested using only one XeCl-excimer laser as pump source. For optimized amplification of DFDL, the three-stage amplifiers were arranged with increasing cross-section and accordingly increasing pump energies. The first AmpI, II stages were dye cell of 5 mm, 10 mm and contained a
[mol/l](solvent : Methanol) of Rhodamine 610. Double-pass amplification in the AmPII was measured to suppress the ASE by using a diffraction grating. The beam intensity of AmpI, II was saturated with a gain of respectively 10 and 48. The last AmpIII was Bethune cell of 30 mm and contained a
[mol/l] (solvent : Ethanol) of Rhodamine 610. In the single-pass and double-pass amplification, the output energy was obtained 168.2
J and 471
High power tunable Ti:sapphire laser with sub-40fs pulsewidth
Korean Journal of Optics and Photonics, volume 10, issue 5, 1999, Pages 430~438
We have utilized soft-aperturing by gain media to develop a high-power tunable Ti:Sapphire laser with sub-40-fs and broad tuning range. The tunable spectral range was only limited by the bandwidth of mirrors. We made use of knife-edge slits near an intra-cavity prism controlled by micro-stepping-motors to tune the center wavelength continuously. The tunability of the center wavelength was ranged from 770 nm to 870 nm, and the measured pulsewidth was sub-40 fs throughout the above spectral range. The shortest pulsewidth was about 17 fs at the center wavelength of 820 nm and the spectral bandwidth was 72 nm. At 5 W pumping power of the Ar-ion laser we obtained average output power of 440 mW~580 mW. For the cw and Kerr-lens mode-lodking conditions, we have evaluated the value of an amplitude modulation to be
from the calculated waists of a Gaussian beam on the Ti:sapphire crystal surface. Using this result we demonstrate that the generation of sub-40-fs Kerr-lens mode-locked pulse can be described by the Ginzberg-Landau model which is a weak pulse shaping model.