• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2020-2021
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• 2004

Distributed optical feedback by gain coupling in V-groove quantum-wire lasers is investigated using InGaAs/AlGaAs active materials grown by metalorganic chemical vapor deposition (MOCVD). In order to avoid grating overgrowth during the fabrication of DFB structures, a newly developed constant MOCVD growth method is employed. Gain anisotropy in emission spectra near Bragg wavelength, resulting from optical feedback along the DFB direction, is clearly observed at room temperature.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.116-117
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• 2002

In recent years, there has been an increasing interest in $Tm^{3+}$ doped crystals and glasses due to their potential applications as near infrared lasers and infrared to visible upconversion lasers for use in different fields such as medical surgery, eye safe laser radar, data storage, barcode reading and so on. Thulium ions have stable excited levels suitable for emitting blue upconversion fluorescence. (omitted)

• International Journal of Internet, Broadcasting and Communication
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• v.4 no.2
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• pp.22-27
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• 2012

The design characteristics of circular vertical-cavity surface-emitting lasers are studied by using a newly developed equivalent network. Optical parameters, such as the stop-band or the reflectivity of periodic mirrors and the resonance wavelength, are explored for the design of these structures. To evaluate the differential quantum efficiency and the threshold current density, a transverse resonance condition of modal transmission-line theory is also utilized. This approach dramatically reduces the computational time as well as gives an explicit insight to explore the optical characteristics of circular vertical-cavity surface-emitting lasers (VCSELs).

• Journal of information and communication convergence engineering
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• v.5 no.4
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• pp.374-376
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• 2007

The output characteristics of HF and DF lasers were compared theoretically. The simulation code shows the good agreement with the experimental results well. As results, the effect of chain termination reaction in $F_2$ rich mixture is larger than that of $SF_6$ rich mixture in HF and DF lasers.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.65.3-65.3
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• 2017

With the advent of high energy/power lasers, extreme conditions, such as those found in astrophysical environments, can be reproduced in laboratory. The scaling between laboratory and astrophysical environments, especially for viscosity and resistivity that govern dissipation processes, is not perfect. Yet, the similarity is close enough to make laboratory experiments relevant for astrophysics. The results have been encouraging, in the sense of suggesting the possibility of exploring fundamental physical processes at play in astrophysical phenomena. In this talk, I will review a few successfully performed and ongoing experiments, such as those for turbulence and magnetic field generation in fluid regime and collisionless shock wave in plasma regime.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.323-324
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• 2007

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.221-223
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• 2002

This paper describes a vacuum tube based high voltage pulse generator for pulsed gas lasers. The pulse generator delivers 20 kV, 300 A pulse outputs with more than 10 kHz pulse repetition rates It can be controlled its Pulse width from 30 ns to 80 ns continuously without any hardware change.

• Journal of information and communication convergence engineering
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• v.8 no.4
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• pp.457-460
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• 2010

we have analyzed tens of Giga pulse signal generation using sideband injection locking scheme. The numerical model for semiconductor lasers under the strong optical injection is based on the Lang's equation and has been extended in order to take into account the simultaneous injection of the multiple sidebands of the current-modulated laser. The numerical simulation results show that the unselected sidebands will affect the optical and RF-spectral characteristics even though the semiconductor laser is locked to the target sidebands.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.3
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• pp.41-46
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• 1992

In this paper we report how to design integrated-mirror etalons for surface-emitting lasers and photonic switching without time-consuming numerical calculation. It consists of the following two-step process (step 1) find the minimum reflectance to achieve the maximum allowable linewidth. (step 2) find the number of the quarter-wave layers in each mirror to realize the reflectance given by step 1. The condition for maximum transmission in an integrated- mirror etalon is also derived. Under this condition we can achieve the required linewidth with the minimum number of quarterwave layers.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.515-516
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• 2006

We have demonstrated three-wavelength Raman fiber lasers using Ge-codoped fiber with 7-pairs of fiber bragg gratings. A slope efficiency of 18.4 % and an total output power of 1.65 W were achieved.