| Co-Investigator(Kenkyū-buntansha) |
IMAI Hajime Fujitsu Laboratories LTD.Manager, 主幹研究員
FUJII Yoichi University of Tokyo, 11S,Professor, 生産技術研究所, 教授 (00013110)
SAKAKI Hiroyuki University of Tokyo, RCAST,Professor, 先端科学技術研究センター, 教授 (90013226)
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| Research Abstract |
The role of large capacity and high speed data transmission optical systems will be more important with the progress of the information human society. For this prupose, the short optical pulse transmission system is promising as well as the coherent optical communication system. In particular, the short optical pulse communication system can be investigated as an extension of the present transmission system. Therefore, the short optical pulse communication system is more practical compared to the coherent communication system within these ten years. However, at present stage, the techique to generate short optical pulses has not been established. In fact, the mode locking system requires external mirrors and the gain switching needs high power. On the other hand, the Q-swicthing is promising to overcome those problems.
In this research program, we fabricated a GaAs quantum well laser with a monolithically integrated modulator and, in addition, an ultrafast optical logic circuit using un
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iform and local pumping optical beams. First, to establish fabrication technique for the integrated quantum well lasers, the fabrication processes are optimized and succeeded in a table 20-30 psec optical pulse generation. In addition, by changing the applied voltage at the modulator section, we demonstrated the wavelength can be controlled. A distributed feedback laser with the two-section was also investigated.
We also fabricated an ultrafast logic operation with two kinds of pumping beam, local and uniform beam in the quantum well lasers. The AND and NOR gate operation were achieved in the device with a switching speed of 10 psec. This type of devices leads to future all optical logic circuit systems.
In summary, we investigated the GaAs quantum well laser with a monolithically integrated modulator, demonstrating its feasibility. In addition, the ultrafast optical logic circuit using uniform and local pumping optical beams was demonstrated in the quantum well lasers. These devices are useful for future high speed optical transmission systems and optical information systems. Less
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