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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 6, Issue 4 - Dec 1995
Volume 6, Issue 3 - Sep 1995
Volume 6, Issue 2 - Jun 1995
Volume 6, Issue 1 - Mar 1995
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Optical Structures of Multilayer Coatings of Antireflection Lenses and their Transmission Characteristics
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 259~265
Antireflection coatings on optical lenses commertially available in domestic market are optically analyzed. Transmission spectra and reflection spectra are collected using spectrophotometers. The apparent absorption spectra around the absorption band edge are dominated by the substrate absorption. The reflection spectra and the apparent absorption spectra at visible region between 400nm and 700nm show very strong correlation to each other except a couple samples. The discrepency observed in the latters are due to an increased absorption in visible region by the substrate, which is negative effect of these samples. An antireflection coating consisted of
is made on c-Si substrate for spectroscopic ellispometry analysis. A film-by-film coating is accomplished and between each film deposition, ex-situ spectroscopic ellipsometry measurements are made. The analysis of the spectroscopic ellipsometry data reveals that the average film densities of
reach only 80% of their respective packing densities and thick films are inhomogeneous along film growth direction. Discussions are made toward in-situ, real-time monitoring of the film growth so that a real-time feedback is possible to achieve a post-correction to minor deviations occured in the previous step. step.
A Study on the Measurement of Spectral Response Characteristics of Color Image Sensor
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 266~273
Colors reproduced by color imaging system are affected by various physical factors. The spectral response of the color image sensor is one of the important factors. We developed a spectral response characteristics measurement system which is composed of optical part and color analyzing part. The data from the optical part was analyzed by the color analyzing part and spectral response characteristics of R, G, B three color sensors were obtained. Using this system, the spectral response characteristics of a CCD color camera was measured. From this result, color rendition and linearity of the camera could be analyzed. This measurement system is
considered to be very useful for the evaluation of color image sensor characteristics. stics.
Scanned-Object Holography: Recording and reconstruction of a Hologram Using a Wave Emitted from a Moving point sourde as object beam
;Marhic M. E.;
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 274~281
The new method of recording and reconstructing a synthetic object, which was called as scannedobject holography (SOH), was proposed and its feasibility was demonstrated theoretically and experimentally. The hologram was recorded by interfering the fixed reference beam with spherical waves emitting from a moving point source, whose trajectory determined the shape of the synthetic object to be recorded. The end face of an optical fiber and the output from a pulsed laser were utilized in order to implement a moving point source experimentally. tally.
Characteristics of a CW Ti:sapphire Laser in a Folded Geometry
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 282~287
We have studied the characteristics of a cw Ti:sapphire laser pumped by an Ar-ion laser. Ti:sapphire is one of the most attractive materials for the generation of ultra-short pulses because of its very broad gain bandwidth. We used a 4.1 mm thick, 0.15 wt. %
-doped, Brewster-angled Ti:sapphire crystal and made a folded cavity to create a strong focusing mode. The folding angle of the cavity was adjusted to
to compensate for the astigmatism from the Brewster-angled Ti:sapphire crystal. 5 WAr-ion laser was used as a pumping source. We observed that the Ti:sapphire cw output power was sensitively changed with respect to the condition of the folded cavity. The threshold pumping power was 2 Wand the slope efficiency was 16% when an output coupler of 10% transmission was used. The maximum output power was more than 450 mW at 5 W pumping. mping.
The Spatial Coherence Characteristics of Wavefront of NBUR Nd:YAG Laser Output Beam
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 288~295
We have studied about spatial wavefront analysis of a pulsed laser output beam by means of an imaging unstable ring resonator with an infinite Fresnel number. We have constructed a Newtonian telescope type NBUR (Negative Branch Unstable Ring) Nd:YAG laser with 4 plane mirrors. Provided that the NBUR resonator is under self imaging condition, the resonator could be reduced diffraction effects which were occuring to the beam transmitting through the circular aperture of scraper mirror in the resonator. We have observed enhancement in the spatial coherence of wavefronts of laser beam due to the iterative round trips of the self imaging beam inside the ring resonator. The information on the spatial wavefronts was determined by the fringe patterns from Mach-Zehnder interferometer and the fringe analysis by means of the Fourier transform method showed the distortion of wavefronts of less than 0.2), In comparison with a standing wave type resonator, we have confirmed that the spatial coherence of the NBUR Nd:YAG laser output beam was enhanced as much as 75%. s 75%.
Construction and Characterization of Travelling Wave Type Single Mode Fiber Laser Using a Fiber Grating
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 296~301
A single-mode erbium-doped fiber laser is constructed by using a intracore fiber Bragg grating and a unidirectional fiber loop mirror. The laser cavity is designed in such a way that the laser beam forms a travelling wave in the gain medium by placing the erbium-doped fiber inside the unidirectional loop and that the wavelength-selective feedback is made from the outside of the loop by a fiber grating with 0.2 nm reflection linewidth. An additional fiber ring resonator is constructed and used as an optical spectrum analyzer to observe the variation of the laser mode spectra. As the result, relatively stable single mode, single polarization output is observed for the most of the time except some mode hoppings in minute scale due to enviommental temperature variations. tions.
Temperature Dependence of the Gain Spectrum of a Quantum Well Laser
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 302~309
We desinged a lattice-matched InGaAs/lnGaAsP quantum well laser that lases at
at room temperature, and calculated the gain spectrum as a function of injected carrier density and temperature. For the calculation of band structures and momentum matrix elements, we used a transfer JIlatrix method based on a block-diagonalized 8x8 second-order Ii
P Hamiltonian. This lattice-matched quantum well lases in transverse electric mode. As the temperature increases, the lasing wavelength gets longer, the transparency carrier density increases, and the differential gain is reduced. The temperature dependence of the gain spectrum comes from the temperature dependence of the band structure and that of the Fermi function, and the latter contributes dominantly.nantly.
Design and fabrication of the
WDM coupler with the PSG waveguide films
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 310~316
We designed the
WDM directional coupler and its coupling length was calculated with the variation of the two waveguide's core separation and other variables by the Fourier transformed scalar wave equation. We deposited the PSG films for optical waveguide by low pressure chemical vapor deposition and fabricated the WDM coupler using the laser lithography and
reactive ion etching process. A V -groove which was made to support and fix the optical fiber is fabricated on Si substrate by chemical etching. The WDM coupler and the V-groove are connected using UV curing epoxy. We found that propagation mode of each port of WDM coupler is single mode and maximum extinction ratio between two out ports is 6 dB for
, and 12 dB for
Circular Polarization Spectroscopy in
line and Laser Frequency Stabilization
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 317~323
Doppler-free circular polarization spectroscopy in 87Rb Dz line has been carried out by using a diode laser whose linewidth was narrowed by an external cavity, and experimental results were compared with an optical pumping polarization spectroscopy theory. A dispersive spectrum obtained in a weak pump beam was completely fitted to a single cycle optical pumping theory. The laser frequency was locked to a Rb atomic hyperfine transition line without any frequency modulation by using the dispersive curve as an error signal. ignal.
Stimulated Brillouin scattering using a source with a few axial modes and an optical fiber ring resonator
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 324~330
Stimulated Brillouin scattering theory is described in an optical fiber. Frequency change with an optical heterodyne method is analyzed between reference signal of a source and stimulated Brillouin scattering signal in an optical fiber. By coupling a source with a few axial modes and an optical fiber ring resonator, Brillouin scattering is studied with a spectrum analyzer. Using reference beating signal of a source, we have reduced the Brillouin beating frequency from 13 GHz range to below GHz. Experimentally, we can see the Brillouin beating frequency from 13 GHz range to below GHz with a dispersion shifted fiber (1.32 GHz), Ti-doped fiber (900 MHz) and single mode optical fiber (870 MHz). MHz).
The Absorption Saturation and Diffraction Efficiency of the Permanent Gratings Due to the Photodarkening in Semiconductor Doped Glasses
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 331~336
The steady-state absorption saturation of the photodarkend SDG was investigated. The absorption saturation intensity was observed to increase for the photodarkened sample. The diffraction efficiency of the permanent grating due to photodarkening was also measured using the backward DFWM technique. For the low backward pump intensity, the diffraction efficiency was proportional to the intensity of the pump beam. The origin of increasing diffraction efficiency is attributed to the difference in absorption between the permanent gratings created by photodarkening. ening.
The Characteristics of Resonant Stimulated Raman Scattering in the water droplet
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 337~344
We have detected the resonant stimulated Raman scattering signal when the Q-switched Nd:YAG laser beam are incident on the
sized water droplet as pump beam. The signals appeared as uniformly spaced peaks and the intervals between peaks become narrow as the droplet size increases. Also we have confirmed the morphology dependent resonances (MDR's) characteristic of the stimulated Raman scattering signal when the water droplet becomes nearly spherical shape after two water droplets are coupled to a droplet. The error in the measured intervals between MDR's of same mode order is about 5%.out 5%.
Propagation Characteristics of Fundamental Dark spatial Solitons on Finite-width Backgrounds
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 345~351
We have studied experimentally the propagation characteristics of fundamental dark spatial solitons on finite-width backgrounds and conpared with the result of numerical simulations. It was verified experimentally that the width of dark solitons decreased but that of background increased as the beam intensity increased. The refractive index change obtained from soliton constant, which is for infinite-width background, was smaller than that from Z-scan method. Numerical simulations of fundamental dark solitons on a finite-width backgrounds showed that the peak intensity of background, the width of dark soliton and the soliton constant varied with the propagation length. If the change of soliton constant on finite-width backgrounds was considered, the refractive index change was in good agreement with that from Z-scan method. ethod.
Faraday Rotation of the Hoya FR5 and FR4 Glasses at Cryogenic Temperature
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 352~358
Measurements of the Faraday rotation and magnetization of terbium-doped Hoya FR5 glass and cerium-doped Hoya FR4 glass have been made as a function of temperature T in the range 4.2 K -10 K and of magnetic field H of up to 80 kG at the
laser wavelength of 514.5nm. The saturations of magnetization and Faraday rotation above H/T>
can be analyzed by the quantum theory of paramagnetism. Calculated parameters show that the large Verdet constant of
glass is due to the effective
electric dipole transition effect and that of
glass is due to the magnetization effect.effect.
A study on the Fabrication of Wavelength Measurement System and the Spectrum Anslysis of Laser Diodes
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 359~364
A wavelength measurement system has been made using a monochromator and computer interfacing. The spectra of several light emitting diodes and the wavelength characteristics of Fabry-Perot LD and DFB LD have been measured with this system. The results show that this system can be practicalIy used in analyzing the lasing mode and the wavelength characteristics of the semiconductor lasers. asers.
A signal processing technique for interferometric fiber-optic sensors
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 365~372
A signal processing technique for interferometric fiber-optic sensors is proposed. It does not require a any special optic components such as phase modulator,
couplers,to obtain the full sensitivity of the interferometer. Instead, it requires a reference interferometer for phase referencing and a reference mirror for intensity referencing, but intensity referencing can be done without using the r reference mirror. The new technique utilizes the frequency chirping of the laser diode to process t the sensor signal with both wide dynamic range and high sensitivity of the interferometer. It was a applied to an internal-mirrored FP interferometric temperature sensor to obtain the system noise of
from I cm FP Interferometor sensor device.
A Trench Structure for Low Bending Loss of Bent Optical Waveguides
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 373~378
Bending losses of bent optical waveguides are calculated by virtue of the finite difference-beam p propagation method in the cylindrical coordinate system. In order to minimize the radiating losses of bent optical waveguides, we apply the trench structure to the bent waveguides and perform the a analysis to keep track of: 1) the influence of curvature radius on the bending loss without the trench, 2) the influence of curvature radius and refractive index difference on the bending loss with the trench, 3) the influence of the trench width on the bending loss.
A Study On The Bending Characteristics of Ribbon Cable Unit
Korean Journal of Optics and Photonics, volume 6, issue 4, 1995, Pages 379~384
In order to construct B-ISDN, it is inevitable to introduce optical fiber of low loss and wide bandwidth. Coincidently, high count optical fiber cable is solely important to form optical subscriber network. The best structure of high count optical fiber cable to achieve multi-splicing as well as high density at the same time is the one of taking optical ribbon as a unit of accomodation. However, since optical ribbon has its own width. optical loss due to length difference during the bending of ribbon cable unit occurs in relatively easy way. Therefore, care should be taken during its manufacturing and storage. In t\1::; paper, strain, bending radius and lateral pressure of each fiber in ribbon due to the bending of ribbon cable unit are caculated theoretically. Hence, we have measured optical loss of each fiber as function of unit bending radius, when we bent the ribbon cable unit on the various reel. We found that the result accords well with the theoretical analysis. The result shows the importance to determine proper radius of reel used in ribbon cable manufacturing and storage. orage.