| Project/Area Number |
04555084
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子機器工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
NAITO Yoshiyuki Tokyo Inst.of Tech., Faculty of Eng., Professor, 工学部, 教授 (70016335)
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| Co-Investigator(Kenkyū-buntansha) |
ANZAI Hiroki Tokyo Inst.of Tech., Faculty of Eng., Research Associate, 工学部, 助手 (80212661)
MIZUMOTO Tetsuya Tokyo Inst.of Tech., Faculty of Eng., Assoc.Professor, 工学部, 助教授 (00174045)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 1993: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1992: ¥12,900,000 (Direct Cost: ¥12,900,000)
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| Keywords | Optical Multi-Demultiplexer / Optical Filter / Mach-Zehnder Interferometer / Waveguide Directional Coupler / Tapered Coupler / Crosstalk / テーパ状結合器 / 光分波・合波器 / 方向性結合器 |
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| Research Abstract |
Optical multi-demultiplexers are essential in wavelength division multiplexing transmission fiber communication systems. In order to reduce the crosstalk, the multi-demultiplexer employing Mach-Zehnder interferometer is investigated in this study.
The directional couplers used in the Mach-Zehnder multi-demultiplexer are required to have the coupling coefficient of exactly 0.5 in the wavelength range in which the multiplexer operates. In this study, we show that the tapered coupler, which changes its waveguide structure along the light propagation direction, is suitable for this. That is, the crosstalk can be reduced by employing the tapered couplers.
The waveguide structure with low refractive index difference between a core and a clad is used to reduce the characteristic degradation due to the deviation of waveguide parameters incorporated in the fabrication process and to obtain the high coupling efficiency between the waveguide and the optical fiber. The multiplexer which has the lowest crosstalk of -22dB with the 5nm channel spacing in the wavelength range between 1.25 and 1.35 mum is fabricated.
To reduce the crosstalk in wider wavelength range, we investigated the design of tapered coupler whose coupling characteristics are less wavelength dependent.
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