1998 Fiscal Year Final Research Report Summary
BROADBAND SPECTRUM ULTRASHORT PULSE GENERATION WITH ARBITRARY REPETITION FREQUENCY EMPLOYING SEMICONDUCTOR LASERS
| Project/Area Number |
09650380
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
TSUCHIYA Masahiro THE UNIV.OF TOKYO DEPT.OF ELECTRONIC ENG.ASSC.PROF., 大学院・工学系研究科, 助教授 (50183869)
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| Co-Investigator(Kenkyū-buntansha) |
KAMIYA Takeshi THE UNIV.OF TOKYO DEPT.OF ELECTRONIC ENG.PROF., 大学院・工学系研究科, 教授 (70010791)
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| Project Period (FY) |
1997 – 1998
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| Keywords | OPTICAL SOLITON / OPTICAL PULSE COMPRESSION / OPTICAL PULSE SHAPING / OPTICAL FIBERS / SEMICONDUCTOR LASER / DISPERSOIN MANAGEMENT / GAIN SWITCHING / NONLINEAR OPTICAL FIBER LOOP |
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| Research Abstract |
Recently, the capacity of fiber-optic signal transmission per an optical fiber is more than several 100 Gbps and exceeding 1 Tbps. What have supported these trends are the wavelength division multiplexing and optical time division multiplexing techniques. In those techniques, one of the most important and fundamental issues is ultrashort pulse generation from semiconductor lasers in the 1500 nm wavelength range. The aim of this research project is to implement a method-to generate broadband spectrum ultrashort optical pulse of high quality by means of fiber-optic compression schemes out of gain-switched semiconductor diode laser pulse having arbitrary repetition frequencies. We have succeeded in the getting the following results. (1) We found out that it is important to take into account the higher order nonlinear effects like the Raman effect and the higher order dispersion effects in optical fibers when we design fiber optic compressors for sub-100 fs pulse generation. (2) According to the above guideline for the design, we implemented a rather simpler soliton compressor and applied it to pico-second gain-switched laser diode pulses. Resultant width of 44 fs was obtained, which is one of the shortest pulses ever obtained in the 1500 nm wavelength range. (3) Furthermore, we constructed nonlinear optical fiber loops to eliminate the pedestals accompanying the ultrashort pulses in the above, and have obtained successful pedestal suppression (>20 dB), which has given resultant 55 fs pedestal free optical pulses. (4) The optical spectra obtained in the pulses thus generated were found to contain fairly broadband spectra of 100 to 250 nm, which are quite attractive for the WDM optical source. We believe thus the goal of the project has been reached and we have established a technology to generate sub-100 fs high quality optical pulses in the 1550 nm wavelength range.
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