• Optical Science and Technology
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• v.14 no.2
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• pp.19-27
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• 2010

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.183-195
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• 2007

MEMS technology is proven to be an enabling technology to realize many components for optical networking applications. Due to its widespread applications, VOA has been one of the most attractive MEMS based key devices in optical communication market. Micromachined shutters and refractive mirrors on top of silicon substrate or on the device layer of SOI (Silicon-on-insulator) substrate are the approaches trapped tremendous research activities, because such approaches enable easier alignment and assembly works. These groups of devices are known as the planar VOAs, or two-dimensional (2-D) VOAs. In this review article, we conduct the comprehensively literature survey with respect to MEMS based planar VOA devices. Apparently MEMS VOA technology is still evolving into a mature technology. MEMS VOA technology is not only the cornerstone to support the future optical communication technology, but the best example for understanding the evolution of optical MEMS technology.

• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.85-92
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• 2007

In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric glass lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical glass molding pressing (GMP) process was developed with an eye to mass production of precision optical glass parts by molding press. In this paper, as a fundamental research to develop the multi-cavity mold for higher productivity of a progressive GMP process used in the fabrication of an aspheric glass lens, an aspheric glass lens forming simulation was carried out.

• Ceramist
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• v.10 no.3
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• pp.15-27
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• 2007

Fabrication and electro-optic applications of glass optical fibers were reviewed. Theoretical description on the electro-optic Kerr effect in glass optical fibers, particularly for the second-order optical nonlinearity was given. Fabrication procedure and the characterization of the nonlinear electro-optic fibers with internal electrodes were described. Several electro-optic devices based on the polarimetric cells made by the nonlinear optical fibers with internal electrodes were also discussed with the experimental results on the electro-optic effect.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.411-412
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• 2008

The chromatic dispersion of the germano-silicate optical fiber incorporated with Si nanocrystals was determined with the aid of simulation and demonstrated using experiments, which showed dependence of the launched power and the pump wavelength due to optical nonlinearity of the fiber.

• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.327-333
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• 2015

This paper reports the fabrication of various micro-lensed single-mode optical fibers through the use of an enhanced peak power $CO_2$ laser beam. The end faces of the optical fibers are exposed to the $CO_2$ laser beam to form convex, concave, and conical shape optical fiber tips. Peak power of the $CO_2$ laser beam was varied from 0.8 W to 1.5 W depending on the shape of the optical fiber tip. We also discover the dependence of the angle of the optical fiber tip on the rotation angle and the number of $CO_2$ laser irradiations. The angle shows an increasing trend with both these parameters. We achieve a wide range of lenticular fibers with end face angle varying from $4.47^{\circ}$ to $8.13^{\circ}$. Furthermore, we investigate the emission pattern of light from the developed micro-lensed fibers. The proposed $CO_2$ laser based optical fiber reshaping technique shows great consistency, and thus is suitable for commercial applications.

• ETRI Journal
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• v.25 no.6
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• pp.531-534
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• 2003

This report describes the effect of optical delay on the suppression of the power transient excursion in a combined gain-controlled erbium-doped fiber amplifier with an internal optical feedback loop (OFL). A simple homogeneous model showed that the optical delay caused a phase change in the oscillation of the surviving and laser channels, which resulted in a reduction of the overall power transient excursion. In addition to the reduction, a real system with a 1528.7-nm OFL shifted the oscillation upward or downward according to channel removal or addition, whereas another one with a 1560.9-nm OFL did not. This different transient behavior reflected a control-wavelength dependence on optical automatic gain control, where spectral-hole burning dominated over relaxation oscillation for 1528.7 nm, and vice versa for 1560.9 nm.

• Journal of the Optical Society of Korea
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• v.7 no.2
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• pp.79-83
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• 2003

In this paper, we describe the fabrication process of a photonic crystal fiber and present the measured optical properties of the photonic crystal fiber. The fabrication of the photonic crystal fiber involves stacking, jacketing, collapsing, and drawing using a conventional drawing tower The photonic crystal fiber drawing needs higher tension to maintain the uniform air hole structure. Thus, the temperature of the photonic crystal fiber drawing is lowered by a few hundred degrees Celsius than for the case of conventional optical fiber drawing. The optical properties of the fabricated photonic crystal fiber such as mode profile, optical loss, transmission spectrum, bending loss, and polarization dependent loss are measured.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.236-243
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• 2018

A series of $Er^{3+}/Yb^{3+}$ co-doped fluorophosphate glasses with varying $YbF_3$ concentration were prepared by a high temperature melt quenching technique. Absorption and emission cross-sections were determined by using the McCumber theory. The larger emission cross-section ($9.86{\times}10^{-21}cm^2$) and longer fluorescence lifetime (12.37 ms) were obtained for the $^4I_{13/2}{\rightarrow}^4I_{15/2}$ transition of ABS3Er4Yb glass. The sensitivity and temperature of the maximum sensitivity were evaluated by the fluorescence intensity ratio method from the measured upconversion spectra. The results were discussed and compared to the other reported glasses.

• Current Optics and Photonics
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• v.2 no.5
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• pp.400-406
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• 2018

The Semiconductor Optical Amplifier (SOA)-based Mach-Zehnder interferometer is a major contributor in all-optical digital processing and optical computation. Optical tree architecture provides one of the new, alternative schemes for integrated all-optical arithmetic and logical operations. In this paper, we propose an all-optical 3-bit integrated parity generator and checker using SOA-MZI-based optical tree architecture. The proposed scheme, able to process input signals at a desired operating wavelength, has been characterized using RZ-modulated signals at 10 Gbps. The maximum extinction ratios achieved at the output of the parity generator and checker are 10 dB and 8 dB respectively.