• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.317-318
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• 2006

• Korean Journal of Materials Research
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• v.29 no.12
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• pp.747-752
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• 2019

Environmental pollution remains a considerable health risk source all over the world; however, hazards are usually higher in developing countries. Iraq has long been suffering from the problem of pollution and how to treat pollution. Photocatalytic degradation has turned out to be most productive process for dye degradation. In this investigation, Rhodamine B (RhB), dye has been selected for degradation under visible light illumination. To address this issue, we fabricate erbium trioxide nanoparticles (Er₂O₃/NPs). Erbium trioxide nanoparticles are prepared and utilized for photo-catalytic degradation. The characterization of Er₂O₃/NPs is described and confirmed by utilizing of XRD (X-ray diffraction) and SEM (Scanning Electron Microscopy). The average size of Er₂O₃ nanoparticles is observed to be 16.00 nm. Er₂O₃/NPs is investigated for its ability of photo-catalytic degradation through certain selected parameters such as concentration and time. The methodological results show that the synthesized Er₂O₃/NPs is a good photo-catalytic for Rhodamine degradation.

• Korean Journal of Optics and Photonics
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• v.21 no.4
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• pp.139-145
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• 2010

A complete modeling of erbium-doped Bismuth-oxide fibers with a high doping concentration is presented. A 6-level amplifier system that incorporated clustering-induced concentration quenching, cooperative upconversion, pump excited state absorption (ESA), and signal ESA, was adopted for the modeling. The accuracy of the modeling was verified by comparing the calculated gain and noise figure with experimentally obtained ones.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.117-120
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• 2004

We demonstrate a fiber-optic sensor scheme, capable of the simultaneous measurement of strain and temperature using a single fiber Bragg grating written in an erbium: ytterbium-doped fiber. This novel and compact fiber grating based sensor scheme can be used for synchronous measurement of strain and temperature over ranges of $1100\;{\mu}{\varepsilon}$ and $50-180\;^{\circ}C$ with rms errors of $55.8\;{\mu}{\varepsilon}$ and $3^{\circ}C$, respectively. The simple and low-cost sensor approach has a considerable potential, particularly for wide-range strain sensing applications in which high resolution is not required.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.342-350
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• 2010

An optimal wideband gain flattened hybrid erbium-doped fiber amplifier/fiber Raman amplifier (EDFA/FRA) has been introduced. A new and effective optimization method called particle swarm optimization (PSO) is employed to find the optimized parameters of the EDFA/FRA. Numerous parameters which are the parameters of the erbium-doped fiber amplifier (EDFA) and the fiber Raman amplifier (FRA) define the gain spectrum of a hybrid EDFA/FRA. Here, we optimize the length, $Er^{3+}$ concentration, and pump power and wavelength of the EDFA and also pump powers and wavelengths of the FRA to obtain the flattest operating gain spectrum. Hybrid EDFA/FRA with 6-pumped- and 10-pumped-FRAs have been studied. Gain spectrum variations are 1.392 and 1.043 dB for the 6-pumped- and 10-pumped-FRAs, respectively, in the 108.5 km hybrid EDFA/FRAs, with 1 mW of input signal powers. Dense wavelength division multiplexing (DWDM) system with 60 signal channels in the wavelength range of 1529.2-1627.1 nm, i.e. the wide bandwidth of 98 nm, is studied. In this work, we have added FRA's pump wavelengths to the optimization parameters to obtain better results in comparison with the results presented in our previous works.

• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.162-166
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• 2014

The impact of booster section length made from passive erbium-doped fiber (EDF) on the L-band multiwavelength Brillouin-Erbium fiber laser (MBEFL) is studied experimentally in this paper. The influence on the performance of MBEFL in term of number of generated Stokes lines, tuning range and lasing threshold were investigated. A comparison was made between MBEFL without a booster section and with booster sections of different lengths. Through comparative study and at fixed BP power and 100mW of 1480 pump power, longer passive EDF length of 5m exhibits the highest average number of Stokes lines of 23 with tuning range of 14nm. In contrast, shorter passive EDF length of 1m shows the highest tuning range of 17nm and an average number of 21 Stokes lines.

• Korean Journal of Optics and Photonics
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• v.6 no.4
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• pp.296-301
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• 1995

A single-mode erbium-doped fiber laser is constructed by using a intracore fiber Bragg grating and a unidirectional fiber loop mirror. The laser cavity is designed in such a way that the laser beam forms a travelling wave in the gain medium by placing the erbium-doped fiber inside the unidirectional loop and that the wavelength-selective feedback is made from the outside of the loop by a fiber grating with 0.2 nm reflection linewidth. An additional fiber ring resonator is constructed and used as an optical spectrum analyzer to observe the variation of the laser mode spectra. As the result, relatively stable single mode, single polarization output is observed for the most of the time except some mode hoppings in minute scale due to enviommental temperature variations. tions.

• The Journal of Advanced Prosthodontics
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• v.6 no.2
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• pp.79-87
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• 2014

PURPOSE. The aim of this study was to determine the efficiency of Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser in different output powers for removing permanent resin cement residues and therefore its influence on microshear bond strength compared to other cleaning methods. MATERIALS AND METHODS. 90 extracted human molars were sectioned in 1 mm thickness. Resin cement was applied to surface of sliced teeth. After the removal of initial cement, 6 test groups were prepared by various dentin surface treatment methods as follows: no treatment (Group 1), ethylene diamine tetra acetic acid application (Group 2), Endosolv R application (Group 3), 1.25 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 4), 2 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 5) and 3.5 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 6). The topography and morphology of the treated dentin surfaces were investigated by scanning electron microscopy (n=2 for each group). Following the repetitive cementation, microshear bond strength between dentin and cement (n=26 in per group) were measured with universal testing machine and the data were analyzed by Kruskal Wallis H Test with Bonferroni correction (P<.05). Fracture patterns were investigated by light microscope. RESULTS. Mean microshear bond strength ${\pm}$ SD (MPa) for each group was $34.9{\pm}17.7$, $32.1{\pm}15.8$, $37.8{\pm}19.3$, $31.3{\pm}12.7$, $44.4{\pm}13.6$, $40.2{\pm}13.2$ respectively. Group 5 showed significantly difference from Group 1, Group 2 and Group 4. Also, Group 6 was found statistically different from Group 4. CONCLUSION. 2 W and 3.5 W Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser application were found efficient in removing resin residues.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.309-313
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• 2008

We studied the sapphire and germanium fibers to determine which optical fiber best transmits Erbium:YAG laser for intracorporeal lithotripsy. Human calculi were ablated with an Erbium:YAG laser in contact mode using two fibers. Optical outputs at the distal end of fibers were measured before and after laser lithotripsy. Upon the irradiation on the calculus with the 50 mJ and 100 mJ pulse energy, the output energy at the distal end of germanium fiber declined to approximately 50% of the input energy. For the sapphire fiber, the output energy at the distal end remained unchanged with 100 mJ input energy; however the output energy had dropped to 50% for 200 mJ input energy. In order to examine how the types of target tissue affect the fiber damage, the sapphire fiber was tested for the irradiation on soft tissue and water as well. No energy decline was observed during soft tissue and water irradiation. We also characterized ablation craters with both optical fibers. Both fibers produced similar craters on calculi in terms of depth and diameter. Sapphire fibers are better suited than germanium fibers for Erbium:YAG lithotripsy in terms of the fiber damage.

• Journal of the Optical Society of Korea
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• v.17 no.2
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• pp.117-129
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• 2013

We briefly review the recent progress in passively mode-locked fiber lasers (PMLFLs) based on semiconductor saturable absorber mirrors (SESAMs) and discuss the detailed characterization of a SESAM-based, passively mode-locked erbium-doped fiber (EDF) laser operating in the 1.5-${\mu}m$ spectral range for various configurations. A simple and compact design of the laser cavity enables the PMLFL to generate either femtosecond or wavelength-tunable picosecond pulses with high stability as the intra-cavity filtering method is altered. All the cavities investigated in our experiments present self-starting, continuous-wave mode-locking with no Q-switching instabilities. The excellent stability of the source eventually enables the wavelength-tunable PMLFL to be used as a master oscillator for a power-amplifier source based on a large-core EDF, generating picosecond pulses of >10-kW peak power and >100-nJ pulse energy.