2005 Fiscal Year Final Research Report Summary
study on nonblocking wavelength switch using microring resonators
| Project/Area Number |
16360031
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Yokohama National University |
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Principal Investigator |
KOKUBUN Yasuo Yokohama National University, Faculty of Engineering, Professor, 大学院・工学研究院, 教授 (60134839)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Photonic integrated circuit / Three-dimensional integration / Microring resonator / Cross-grid topology / Wavelength selective switch / Vertical coupling / Hitless / Vernier effect |
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| Research Abstract |
Tunable Add/Drop filter is a key device for flexible and scalable routing using wavelength label. However, the conventional tunable filter blocks other wavelength channels during the tuning of resonant wavelength. Thus we proposed a nonblocking wavelength selective switch (WSS) by controlling individually resonant wavelengths of double series coupled microring resonator. The switch is based on the operational principle that in the double series coupled microring resonator the drop port output at a specific resonant wavelength is obtained in simultaneous resonance of both ring resonators and is not obtained when resonant wavelengths of two ring resonators are not matched. In this research, we are aiming at realizing the nonblocking wavelength selective switch based on this principle.
In the fiscal year of 2004, we demonstrated a nonblocking wavelength selective switch using polymer material, because polymer materials have large thermo-optic coefficient and can realize a wide tuning range. However, the reproducibility of resonant wavelength (0.16nm) and the response time (2ms) were not satisfactorily good. Thus in the fiscal year of 2005, we fabricated a nonblocking WSS using Ta_2O_5-SiO_2 dielectric material as core and SiO_2 as cladding. As the result, the response time was extremely improved to 15μs, which is hundred-fold improvement compared with the polymer device, and the reproducibility of resonant wavelength was also improved to less than 0.01nm. However, since the thermo-optic coefficient of dielectric material is one-tenth smaller than that of polymer materials, the tuning range was only 2.3nm. Therefore, we introduced the Vernier effect owing to two different ring radii and successfully improved the tuning range to 23nm, and also demonstrated the dual-directional wavelength switching to both longer wavelength side and shorter wavelength side.
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