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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 fluorecence decay times of single molecules in solution
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 1~4
A confocal microscope system was used to study the bursts of fluorescence photons from single dye molecules excited at 638 nm by a short-pulsed diode laser with a repetition rate of 17 MHz. A red dye, JA22, in ethylene glycol solution was used as a sample. The fluorescence decay curves of single molecules were acquired using a time-correlated single photon counting and analyzed by a maximum likelihood estimator. It was possible to measure the fluorescence decay times with an error probability of 21% at photon number of more than 40 per dye molecule.
Optically induced rotation of combined Mie particles within an evanescent field of a gaussian beam
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 5~9
We demonstrate a windmill type rotation of combined Mie particles caused by the evanescent field generated at the surface of a Gadolinium Gallium Garnet prism where a linearly polarized Nd:YAG laser beam (of wavelength 532 nm and power 100 mW) is totally reflected. The combined particles (e.g., doublets, triplets or quadruplets) consisting of polystyrene latex (or yeast) spheres with diameters of 3~5 m are reported to rotate at 0.1~1 rpm in water when the particles are slightly displaced from the center of the evanescent field.
One dimensional inhomogeneous phase modulation effects on the MTF of an optical system
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 10~14
One dimensional inhomogeneous phase modulation effects on the MTF of optical system was investigated. The lens under test was a doublet made in Korea. It was 36 mm effective diameter, 128.04 mm effective focal length. The ray-fans and spot diagrams were calculated and presented on the picture for on-axis and off-axis (field of view,
). Phase modulation was carried out by positioning a phase modulator close contacted with the lens under test. One was linear type that had linearly increasing phase retardation and the other was stepped type which had phase difference
for each step. The MTFs were measured on the Gaussian image plane and were compared with one another. The MTFs of linear type phase modulated apertures had a little lower values than the MTF of unmodulated aperture for on-axis but most of all the MTFs of one dimensional phase modulated aperture are improved than the MTF of unmodulated aperture.
Optical system design for laser scanning unit
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 15~20
Laser Scanning Unit (LSU), which is one of the core parts of laser printer, consists of LD Module, cylinder lens, polygon mirror and f
lens. After making an initial design on each part, we optimized the one which satisfies the user specification. The optimized optical system has diffraction limited performance for the slit size of 2.7 mm
1.6 mm, f
characteristics less than 0.3% and field curvature less 1.2 mm. We also calcurate tolerance of each part based on RSS(Root Sum Square) method to manufacture LSU for mass production.
Calibration of monodisperse polystylene spheres of size from 1 to 10
by using optical array sizing method
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 21~26
The technique for calibrating standard particles larger than 1
m by using an optical array sizing method has been established. The system consists of an optical microscope with transmission light source, a CCD camera, and a computer equipped with a frame grabber. The center distance between two spheres located at both ends of a row which consists of N spheres is measured in terms of pixel numbers, and divided by (N-1) to obtain the average pixel numbers per particle. This value is multiplied by length conversion constant, which has been determined in advance, to obtain the mean diameter of polystylene spheres. The length conversion constant is found from the microscopic image of calibrated standard stage micrometer plate. In order to reduce error in finding center positions of the scale and particles in the image, a software filter which dilates bright (or dark) object has been used. Spheres having nominal size of 1, 2, 3, 5, and 10
m were measured, and the maximum deviation of the measured mean diameter valus from their certified values was 0.7%. Standard particles which is larger than 1
m can be calibrated by this method with measuredment uncertainy (k=2) lees than 1.53%.
Fabrication of a holographic reflector for reflective LCDs
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 27~31
We designed and fabricated a monocolor holographic reflector for reflective LCDs with DuPont holographic photopolymer as a holographic recording media. By recording at 514 nm as holographic operating wavelength, it was possible to get the brightest image in green color. High contrast ratio is possible due to misalignment of the images with surface reflection and we achieved on/off contrast ratio of 6:1 by applying the fabricated holographic reflector to a TN-LC cell.
반사형 강유전성 액정 공간 광 변조기를 이용한 CGH의 양자화 방법에 따른 재생 특성 비교
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 32~39
In this paper, we made CGH patterns that had continuous amplitude distribution binary coded patterns with two different methods, and analyzed those patterns by using LCSLM (liquid crystal spatial light modulator). The error diffusion algorithm and direct quantization method were used as the binarization methods. The parameters of overall average brightness, mean square error, and diffraction efficiency were used in the comparison of reconstruction characteristics. The LCSLM which we used in this experiment was a binary reflective ferroelectric liquid crystal spatial light modulator addressed electrically with 256
256 pixels, 87% fill factor and 15
m pixel pitch.
Modification of effective index method for a fast and accurate beam propagating computational analysis of optical waveguide devices in 3-dimensional struture
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 40~46
We present a new modified effective index method which can be used to analyze lightwave circuit devices in 3-dimensional structure fast and accruatly using 2-dimensional BPM (beam propagating method). This method can analyze the devices with the cross-section of rectangular, ridge, or similar shapes accurately but more quickly than the 3-dimensional BPM, which is impractical to use on account of long calculating time. As an example, we showed that the calculation error of coupling length in a directional coupler by this method is significantly less than the 2-dimensional BPM using the effective index method.
Light-induced changes of refractive indices and dispersions of
-doped fibers of various doping concentrations
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 47~52
This study describes a simple and effective experimental determination of pump-power dependence of refractive indices and dispersions of erbium-doped fibers (EDFs) of various doping concentrations. Systermatical analysis on light-induced change of the refractive indices and dispersion for a signal wavelength range of 1510 nm-1560 nm with a pump of 980 nm wavelength has been made by measuring the pump-induced phase changes of the signal beam in Mach-Zehnder type interferometer, which has an optically pumped EDF and a reference EDF in each of the two arms, respectively. The measured pump-induced refractive indices match well with the theoritically predicted ones. The results show that pump-induced refractivity and dispersion changes of the EDF increase with the increasing pump power and
-doping concentration as expected from theory.
Output characteristics and measurement of the gain coefficient of a pulsed Nd:YAG laser
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 53~57
We established the laser oscillator using Nd:YAG crystal grown at Ssang Yong company in Korea and investigated the characteristics of oscillation, Q-switching and wave front of output beam. We measured the single pass gain by controlling the threshold input energy with two output couplers of different output reflectances. Moreover, we compared the gain measured by different output couplers with the gain directly measured by the laser amplifier. The peak power of Q-switching, the pulse width, and the single pass gain coefficient at the threshold energy were 1.5 MW, 30ns, and 0.0958 cm-
respectively and they were compared with those of the commercial Nd:YAG crystal. Our crystal was proved to be as good as the commercial crystal.
Harmonically mode-locked semiconductor-fiber ring laser and the output pulse compression
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 58~63
A 10 GHz harmonically mode-locked semiconductor-fiber ring laser was implemented using a semiconductor optical amplifier at
The laser pulse has 13~18 ps pulse duration, 0.4~0.6 nm spectral width and was positively chirped. The output pulse with an average power of 4 dBm was compressed to 6.8 ps using 2 km long standard single mode optical fiber.
Transmission of 10 Gb/s optical signais over 320 km of a dispersion shifted fiber
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 64~67
We have been implemented 10 Gb/s-320 km of dispersion-shifted fiber (DSF) transmission. The optical link consists of a 10 Gb/s optical transceiver, an optical booster amplifier, 3 sets of optical in-line amplifiers, an optical preamplifier and transmission fibers. Firstly, we investigated the Q-factor characteristics in terms of optical signal to noise ratio (OSNR) of 320 km of DSF, measured receiver sensitivity is -27 dBm and power penalty is 2 dB, respectively. We concluded that optical SNR degradation and path penalty gives rise to 1 dB penalty, respectively.
Pulsewidth measurement by self-heterodyne in a frequency shifted feedback fiber soliton laser
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 68~72
We demonstrate a new pulse characterization scheme relying on self-heterodyning that uses intracavity frequency shifter in a fiber soliton laser with frequency shifted feedback. By heterodyning the frequency-shifted pulse stream with the unshifted one, and by measuring the beat strength with varying the delay length between two pulse streams, we obtain the amplitude autocorrelation function from which we estimate the pulsewidth. The result is in good agreement with that obtained by the autocorrelation relying on the second harmonic generation.
Fabrication of semiconductor optical switch module using laser welding technique
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 73~79
Semiconductor optical switch modules of 1
4, and 4
4 types for 1550 nm optical communication systems were fabricated by using laser welding technique, embodying in 30-pin butterfly package. For better coupling efficiency between switch chip and optical fiber, tapered fibers of 10~15mm lens radii were used, which provided up to 60% optical coupling efficiency. With the help of new laser hammering process, we could recover the lost optical power almost completely up to average 82% of initially obtained power. The fabricated optical switch modules showed good thermal stability of less than 5% degradation even after 200 times thermal cycling test. The 2.5 Gbps optical transmission characteristics of the 4
4 switch module showed low sensitivities of less than -30dB for all possible switching paths. The transmission penalties of 1
2 switch module at
BER were 0.6dB and 0.7dB for 50Xm and 90 Km optical fibers, respectively.
Modeling of free carrier absorption coefficients in anisotropic semiconductor quantum well structures
Korean Journal of Optics and Photonics, volume 10, issue 1, 1999, Pages 80~86
The theoretical modeling of free carrier absorption in quantum wells grown on anisotropic materials is presented for the first time. The intersubband and intrasubband free carrier absorption are distinguished and the contribution of each subband to them is calculated separately. The calculated results are compared with the experimental values of
-doped Si quantum wells in literature.