• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.280-287
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• 1992

The nonlinear optical properties of semiconductors and semiconductor microstructures have been the subject of intense research, not only from a fundamental physics point of view, but also for their potential applications to future opto-electronic devices. In this paper, steady-state and time-resolved nonlinear optical spectroscopic techniques to investigate the microscopic world of semiconductor materials were briefly described.

• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.130-132
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• 2007

The characteristics of $S\breve{o}lc$ filters in $X^{(2)}$ nonlinear photonic crystals, periodically poled lithium niobate ($LiNbO_3$), were investigated by the Jones matrix method. The transmittance increases and the full width half maximum of the filter becomes narrow as the duty ratio increases. However, the filtering wavelength does not change. The transmittance at the filtering wavelength is over 95% when the duty ratio is larger than 0.35.

• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.507-510
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• 2001

A numerical analysis based on the nonlinear Schroedinger equation is presented to analyze the propagation stability of the average soliton in a simple nonlinear amplifying loop mirror. The ratio of amplification period to soliton period and the length fraction of the erbium-doped fiber in the loop are varied to investigate their effects on the soliton stability. It is observed that stable soliton propagation is obtained even when the amplification period is only slightly shorter than the soliton period when the length fraction of the erbium-doped fiber in the loop is small, which is different from the previously published condition for stable average soliton propagation.

• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.289-293
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• 1999

The nonlinear susceptibilities of the porous silicon surface were determined from the second harmonic generation. The value of nonlinear susceptibility, ${\chi}^{(2)}_{zzz}$ was $1.04{\times}10_{-7}$ esu which had an intensity of two orders of magnitude greater than that of silicon crystal wafers. The orientation angle of absorbed molecules on the porous silicon surface was ${16.8}^{\circ}$.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.258-262
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• 1996

The physiological systems have nonlinear complex phenomena. Expecially, the flow of capillary blood vessel has a nonlinear dynamic system. Thus, this study analyzes nonlinear characteristics of the flow of capillary blood vessel in physiological systems using chaotic tools(phase space reconstruction, correlation dimension, largest lyapunov exponent). Experimental data have been acquired from examining 10 rabbits. The results of chaotic analysis showed a decreasing largest lyapunov exponent and correlation dimension according to increasement glocose index. And we also know the chaotic behavior.

• Korean Journal of Optics and Photonics
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• v.1 no.1
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• pp.40-45
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• 1990

Optical pulse compression in a high finesse nonlinear Fahry-Perot interferometer made hy a silicon is ohserved. The optical pulse compression and moclul,ltion in a such nonlinear Fabry-Perot interferometer is due to the refractive index change of the silicon hy absorbing the incicknt pulse and generating electron-hole pairs. The pulse is compressed to liS of width of the IIlcicient pulse. And the experimental results are consistent with the results of computer simulation.lation.

• Current Optics and Photonics
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• v.7 no.6
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• pp.708-713
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• 2023

A robust all-fiber nonlinear amplifying loop-mirror-based mode-locked femtosecond laser is demonstrated. Power-dependent nonlinear phase shift in a Sagnac loop enables stable and power-efficient mode-locking working as an artificial saturable absorber. The pump power is adjusted to achieve the lowest intensity noise for stable long-term operation. The minimum pump power for mode-locking is 180 mW, and the optimal pump power is 300 mW. The lowest integrated root-mean-square relative intensity noise of a free-running mode-locked laser is 0.009% [integration bandwidth: 1 Hz-10 MHz]. The long-term repetition-rate instability of a free-running mode-locked laser is 10^-7 over 1,000 s averaging time. The repetition-rate phase noise scaled at 10-GHz carrier is -122 dBc/Hz at 10 kHz Fourier frequency. The demonstrated method can be applied as a seed source in high-precision real-time mid-infrared molecular spectroscopy.

• Bulletin of the Korean Mathematical Society
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• v.54 no.4
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• pp.1195-1219
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• 2017

In this paper, the limit behavior of solution for the $Schr{\ddot{o}}dinger$ equation with random dispersion and time-dependent nonlinear loss/gain: $idu+{\frac{1}{{\varepsilon}}}m({\frac{t}{{\varepsilon}^2}}){\partial}_{xx}udt+{\mid}u{\mid}^{2{\sigma}}udt+i{\varepsilon}a(t){\mid}u{\mid}^{2{\sigma}_0}udt=0$ is studied. Combining stochastic Strichartz-type estimates with $L^2$ norm estimates, we first derive the global existence for $L^2$ and $H^1$ solution of the stochastic $Schr{\ddot{o}}dinger$ equation with white noise dispersion and time-dependent loss/gain: $idu+{\Delta}u{\circ}d{\beta}+{\mid}u{\mid}^{2{\sigma}}udt+ia(t){\mid}u{\mid}^{2{\sigma}_0}udt=0$. Secondly, we prove rigorously the global diffusion-approximation limit of the solution for the former as ${\varepsilon}{\rightarrow}0$ in one-dimensional $L^2$ subcritical and critical cases.

• Korean Journal of Optics and Photonics
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• v.6 no.2
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• pp.135-141
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• 1995

Phenomenological nonlinear gain saturation effect on the noise characteristics of a multi-electrode DBR laser, when the lasing wavelength changes continuously, is presented theoretically. Using the optical transmission line theory, noise characteristics reliant on output power are analyzed by taking into account both the spontaneous enhancement factor K due to the distribution of the spontaneous emission along the active cavity and the nonlinear gain saturation effect. Spontaneous emission rate was increased due to an increase in injected current into the passive section, which in turn lead to increase in relative intensity noise (RIN) and frequency noise. Phenomenological nonlinear gain saturation was found to have significant effect on RIN and frequency noise characteristics. However. Iinewidth was found to decrease due to a phenomenological nonlinear gain saturation effect. ffect.

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.168-174
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• 1998

We have measured nonlinear refractive index and nonlinear absorption coefficient of optical materials by using a far-field phase modulation technique. The phase variation of the probe beam in the nonlinear material is transformed into the spatial phase modulation in the far-field so that the spatial distribution of the optical intensity in conjunction with the computer simulation analysis can give the nonlinear optical constants. We have obtained the nonlinear refractive indices and nonlinear absorption coefficient of $CS_2$ and $BaF_2$ by fitting the experimental values and numerical simulation analysis of far-field measurements. The nonlinear refractive indices of $CS_2$ and $BaF_2$were obtained as $1.2{\times}10^{-11}$ esu and $1.0{\times}10^{-13}$ esu, respectively at 616 nm, and the nonlinear absorption coefficient of BaF$_2$as $5.0{\times}10^{-11}$cm/W at 308nm. These measured values were in good agreement with previous reports.