| Co-Investigator(Kenkyū-buntansha) |
MASUDA Tadahiro Toyohashi University of Technology, Department of information and Computer Sciences, Research Associate, 工学部, 助手 (50293759)
HUANG Xinmin Aichi University of Technology, Department of Electronics and Information Engineering, Associate Professor, 助教授 (00262973)
GOTO Nobuo Toyohashi University of Technology, Department of information and Computer Sciences, Associate Professor, 工学部, 助教授 (60170461)
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| Research Abstract |
Based on examination, we could obtain the following results in research of compact, broadband and high gain integrated amplifiers and circuits using Er doped garnet crystal thin-film.
1. As for devices which Er doped and Er-Yb co-doped garnet thin film on YAG using the RF sputtering system, and device which Er:YIG thin film fabricated on GGG substrate, we evaluated many kinds of composition and crystalline structure, and compared those with conventional Er doped YGG crystal thin film. We finally reached a conclusion on the most suitable material structure. We have fabricated Ce, Bi doped YIG crystal thin film using LPE which was superior in crystal quality and growth controlling. And investigated the condition of fabricating crystal thin film, optimized it.
2.We have measured the absorption and fluorescence spectrum of Er doped garnet thin film, and reached conclusion on the most suitable pump and signal light wavelength. Further more, using 1.5 μm region wavelength tunable laser measure
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d the loss of the waveguide on the most suitable wavelength, measured the absorption loss on the most suitable wavelength.
3.We have carried out the theoretical analysis of static amplification characteristics under the steady-state condition. In the case of Er/Yb co-doped, compared with the case of Er doped only, we obtained high gain per unit length, and found it is desirable to miniaturize the device. We found that the amplified gain depending on the length of waveguide varied with Yb ion. And we optimized Yb ion concentrations.
4.We have carried out the investigation on the static propagating property of pump light and signal light on the waveguide amplifier of which using Er/Yb co-doped garnet crystal thin-film. And we have done the study that the gain and noise properties depend on ion concentrations and propagated distance. Using a high precision laser scanning system, we made three-dimension waveguide, and expected improvement of amplified gain and efficiency.
5. Considered the property of gain spectrum and waveguide dispersion, we have carried out the data analysis on transitional response of ultra short optical pulse amplifications for rare-earth ion, using time dependence 3 energy level and 4 energy level Rate equation. Comparatively studied on Er and Er-Yb doped amplification waveguides, we found that the shape of amplified outgoing pulse will become nonlinear. We have carried out theoretical analysis of dynamic gain property in the optical pulse of nano- and pico-second durations, and also did in femto-second durations. We have studied on the realization of the information processor (ultra fast, ultra parallel computer) which makes it possible ultra fast optical communication signal gain and high speed computing process.
In future, we must examine improvement of amplification characteristics, efficiency, broadbandness and compactness. According to the results of research project, it has become possible more comprehensive study and development. Less
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