• Korean Journal of Optics and Photonics
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• v.4 no.4
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• pp.434-441
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• 1993

Focusing geometry dependence of output Stokes energy in single pass methane Raman shifter is investigated. The experimental result shows that the threshold energy decreases as confocal parameter increases. This result can be explained by gain suppression caused by Stokes - anti-Stokes coupling. In this paper, we give simple analysis for the focusing geometry dependence of Stokes - anti-Stokes coupling and present the criterion of confocal parameter to reduce the gain suppression. Focusing geometry dependence of stimulated Brillouin scattering is measured and the result is in good agreement with theoretical prediction.

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.208-218
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• 2008

We investigate the effect in terms of yield of the reflectivity of both facets and of the phase of a phase tuning section on the self-pulsation (SP) characteristics of multisection complex-coupled (CC) DFB lasers with self-pulsation frequency of the THz region. When the grating phases on both facets of a multisection CC DFB laser are fixed as 0, the variation of SP frequency increases as the reflectivity of both facets increases, while that of SP frequency decreases as the coupling ratio (CR) and the coupling strength increase. For the coupling strength of 3, the range of the phase of a phase tuning section with yields greater than 80% decreases as the CR and the reflectivity of both facets increases. For the coupling strength of 4, the range of the phase of a phase tuning section with yields greater than 80% increases as the CR and the reflectivity of both facets increases.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.114-118
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• 2000

The paper presents the effects of outpLlt-coLLpling power and small SIgnal gain of a He-Se+ laser by discharge of either $^4He$ or $^3He$. A quartz plane-plate was installed to outpLlt-coLlple the laseI beam from the resonator in the eAperimental setup. The result shows tbat compared with those of ~He, tbe outPLlt-coupling power and small-signal gain of $^4He$ increase in the most of the lines. EspeCIally, the small-signal gain of $^3He$ for the strong lines (497.6 nm, 499.3 nm, 506.9 urn, 5176 nm, 522.8 mn, 530.5 nm) lies 25% higher than Ulat of 4He, and the output-coupling power doubles oubles

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.30-31
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• 2000

파장 분할 다중 방식을 사용하는 모든 전광 통신망은 파장 재사용과 routing를 위해 반드시 파장 변환기를 필요로 한다. 본 논문에서는 반도체 광 증폭기와 반도체 레이저를 수평 결합시킨 새로운 구조를 제안함으로써 기존의 파장 변환기가 가졌던 문제점들을[1][2][3] 해결하고자 한다. 두개의 모드가 약하게 결합되었을 때는 그 파의 크기나 전파상수는 서로 영향을 미치게 된다. 예를 들면 수평결합 파장가변 LD[4]나 방향성 결합 파장 변환기[5]는 이 특성을 이용한 소자이다. 본 논문에서 제안된 소자도 이러한 결합모드 특성을 이용하였다. (중략)

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.60-65
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• 2002

The purpose of this study is to measure and compare the output power characteristics and optical gain for selenium vapour laser depending on the He gas purity. The purity of the He gas was improved with a special He-filter. During the measurement the individual wavelengths were selected with a birefringent filter. The result shows that compared with those of laser without He-filter, the output-coupling power and small signal gain of laser with He-filter increase in the most of the lines. Especially, the output-coupling power and small signal gain for the strong lines (497.6 nm, 499.3 nm, 506.9 nm, 517.6 nm, 522.8 nm, 530.5 nm), blue(460.4 nm, 464.8 nm) and red(644.4 nm 649.1 nm) lines lies notably higher.

• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.42-51
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• 2012

In this paper, injection-locking characteristics versus active layer structures in Fabry-Perot laser diodes (FP-LD) are compared. TE and TM gain spectra and peak gains versus carrier density in polarized and unpolarized multiple quantum well structures and in an unpolarized bulk structure are calculated. The calculated gain parameters are applied to a time-domain large-signal model to simulate the injection-locking characteristics. The results show that RIN in unpolarized FD-LDs is about 3 dB lower than that in a polarized FP-LD and that the eye characteristics of the unpolarized FP-LD are much better than those of the polarized FP-LD.

• Korean Journal of Optics and Photonics
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• v.11 no.1
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• pp.37-42
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• 2000

We have numerically solved rate-equations of semiconductor optical amplifier (SOA) to understand the characteristics of SOA. The rate-equations we have used can describe injection carrier density, amplified spontaneous emission and signal photon density in spatial and time domain by dividing the cavity into multi-section. We have investigated injection carrier density, amplified spontaneous emission and signal photon density as a function of position and time in the case of single channel input in the form of square pulse. Also we have analyzed the non-linear phenomena of SOA in the case of injecting multi-channel wavelengths as in WDM. Intermodulation distortion (IMD) caused by beat among channels has significant effects on the signal distortion as the channel spacing becomes narrower, and channel crosstalk becomes larger as the power of signals increases. In the case of the injection of another CW laser whose wavelength is far enough from the signal wavelengths, the crosstalk and the output signal distortion can be significantly reduced. duced.

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.323-332
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• 2007

The effect of the reflectivity of both facets and the phase of a phase tuning section on the self-pulsation (SP) characteristics of multisection complex-coupled (CC) DFB lasers is investigated in terms of yield. The lasers are composed of two CC DFB sections and a phase tuning section between them. As the coupling strength and the coupling ratio (CR) decrease, the effect of the reflected fields from both facets and the other DFB section on the mode characteristics of one DFB section increases, so that the yield decreases. As the facet reflectivity increases, the maximum yield and the range of the phase of a phase tuning section with yield more than 60% decrease independent of the coupling strength and CR. The yield characteristics of CR=0.2 are better than those of CR=0.1 with the same coupling strength due to the larger complex coupling effect. The case with ${\mid}{\kappa}L{\mid}=3$ and CR=0.2 shows best yield characteristics among the cases considered in this work.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.390-395
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• 2002

We studied 100 ${\mu}{\textrm}{m}$ DuPont photopolymers (HRF-150-100) for characteristics of hologram formation and shrinkage at 514 nm with various grating spacings and light intensities. For combinations of rotational and angular multiplexings, we employed two different techniques by rotating the photopolymer and the reference beam. We also performed shift-rotational multilpexing with the rotating reference beam.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1207-1215
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• 2004

A Gigabit Ethernet upstream transmission over a WDM-PON employing remotely wavelength-locked Fabry-Perot lasers has been demonstrated. We have successfully demonstrated a WDM transmission of four Gigabit Ethernet channels with 100 GHz channel spacing over 30 km conventional single mode fiber. The measured f-factor was larger than 17.1 dB. We have also investigated the beating noise characteristics of a wavelength-locked Fabry-Perot laser and showed the remotely wavelength-locked Fabry-Perot laser suppresses the intensity noise of the incoherent light injected, which cause a 6.3 dB SNR improvement compared with that of the conventional spectrum-sliced light source.