• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.270-273
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• 1998

We have demonstrated the wavelength tunable ultrashort pulse fiber ring laser proposed the novel method for measuring the cavity loss from relaxation oscillation frequency and the pump power. To suppress the polarization instability the laser cavity is configured with polarization maintaining fibers and to control the center wavelength a 2.4 nm bandwidth tunable wavelength filter was inserted in the cavity. The laser has 8 picosecond pulse width, 10 GHz repetition rate and 1.2 mW average power in 1530-1560 nm operation range.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.8
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• pp.53-61
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• 1998

Dynamic characteristics of widely tunable SGDBR/SSGDBR laser diodes integrated with an electroabsorption modulator is inestigated using an improved large-signal timef-domain model. First, wide tunning properties of a SGDBR laser diode and a SSGDBR laser diode are analyzed respectively and compared with each other. And, intensity-modulation characteristics of a SGDBR laser diode incorprating an electroabsorption modulator are investigated. It is shown that an external modulation has the lower frequency chirp by 1/20 for almost same extinction ratios than a direct modulation, and a nearly transform-limited pulse train can be generated using the optical gating of an electroabsorption modulator.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.235-238
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• 2008

In this paper, we have developed wavelength swept laser system for the swept source optical coherence tomography(SS-OCT). A laser is constructed by using the two SOAs parallel configuration, fiber Fabry-Perot tunable filter(FFP-TF). The wavelength sweeps are repetitively generated with the repetition period of 50Hz. The wavelength tuning range of the laser is more than FWHM of 80nm centered at the wavelength of 1310nm and the line-width of the source is 0.12 nm.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.98-99
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• 2012

Deposition of thin films using magnetron sputtering plasmas is a well-developed, classical technology. However, detailed investigations using advanced diagnostics are insufficient in magnetron sputtering, in comparison with plasma-aided dry etching and plasma-enhanced chemical vapor deposition. In this talk, we will show examples of diagnostic works on magnetron sputtering employing metal targets. Diagnostic methods which have fine spatial resolutions are suitable for magnetron sputtering plasmas since they have significant spatial distributions. We are using two-dimensional laser-induced fluorescence spectroscopy, in which the plasma space is illuminated by a tunable laser beam with a planer shape. A charge-coupled device camera with a gated image intensifier is used for taking the picture of the image of laser-induced fluorescence formed on the planer laser beam. The picture of laser-induced fluorescence directly represents the two-dimensional distribution of the atom density probed by the tunable laser beam, when an intense laser with a relatively wide line-width is used. When a weak laser beam with a relatively narrow linewidth is used, the laser-induced fluorescence represents the density distribution of atoms which feel the laser wavelength to be resonant via the Doppler shift corresponding to their velocities. In this case, we can obtain the velocity distribution function of atoms by scanning the wavelength of the laser beam around the line center.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.247-248
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• 2003

Tunable diode laser absorption spectroscopy (TDLAS) has been widely used in environmental monitoring of gaseous species in the past decade. TDLAS is a direct measurement technique for pollutants such as NOx without any interference from other species. Because of its superior spectral purity (～0.001 ­$cm^{-1}$), absorption linewidths with resolvable rotational structure can be studied in the mid infrared region where strong fundamental vibrational transitions of molecules appear. (omitted)

• Korean Journal of Optics and Photonics
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• v.21 no.5
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• pp.181-184
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• 2010

A simple technique for a flexibly tunable and switchable dual wavelength-switchable erbium-doped fiber (EDF) laser using fiber Bragg gratings is proposed and demonstrated by using both linear cavity loss controlling and homogeneous gain broadening of the EDF. The oscillating wavelength switching is successfully realized by using the modulation of the acousto-optic modulator driven by the RF signal. The wavelength spacing and lasing wavelength of the proposed wavelength-switchable laser can also be controlled by using the bending-induced tension or compression strain. The proposed tunable dual wavelength-switchable fiber laser has a lot of advantages, such as a high extinction ratio larger than 40dB and a high tunability of ~7.2 nm/$m^{-1}$.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.181-187
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• 1993

Optogalvanic spectrum of Ne has been obtained in the visible wavelength region 550-600 nm by using pulsed tunable dye laser. The recorded laser wavelengths are calibrated on the basis of the accurately-known Ne atomic transition lines. The accuracy of the measured wavelength is ${\pm}$ 0.005 nm. We tabulated the wavelengths and the relative intensities of the OG signals which are useful to calibrate the dye laser using R-590, R-610 dyes.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.7 s.337
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• pp.13-20
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• 2005

We propose an erbium-doped fiber ring laser whose multi-wavelength oscillation is tunable and switchable by tuning fiber bragg gratings. By applying axial pressure on the fiber bragg grating, the wavelength spacing of the proposed laser can be tuned continuously. And by adjusting a polarization controller(PC), the proposed laser can be switched among dual-, triple- and four-wavelength lasing operations.

• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.16-20
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• 1995

We have studied the spectral narrowing characteristics of the tunable Ti:sapphire laser pumped by the second harmonic generation of Nd:YAG laser. Ti:sapphire laser has uniform excitation distribution by both-side end pumping. We have controlled the angle of grating linearly and achieved the continuous selection of wavelength in the broad range from 705 to 835 nm. The output energy of $380{\mu}J$ at 790 nm. the spectral linewidth of $0.13cm_{-1}$ and the beam divergence of 1.2 mrad have been obtained. The wavelength range with power more than 50% of maximum output was 730-825 nm.825 nm.

• Journal of the Optical Society of Korea
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• v.8 no.1
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• pp.13-16
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• 2004

A widely tunable SG-DFB (Sampled Grating Distributed Feedback) laser diode is proposed and its feasibility is confirmed through simulation. The new SG-DFB laser diode is composed of a pair of sampled gratings, some parts of which are gain sections and the other parts of which are phase control sections. It is shown that a few tens of nanometers can be tuned through the adjustment of two currents into the phase control sections. Higher output power is expected compared with a SG-DBR laser diode with similar parameters. The dynamic single mode operation is also observed in the time-domain simulation.