Dr. Shu Namiki Profile

Dr. Shu Namiki

Senior Research Scientist at National Institute of Advanced Industrial Science

SPIE Involvement:

Author

Proceedings Article | 4 March 2022 Presentation + Paper

Functional block-based disaggregation approach for optical network automation supporting diverse node structures

K. Ishii, S. Namiki

Proceedings Volume 12027, 120270G (2022) https://doi.org/10.1117/12.2607322

KEYWORDS: Mathematical modeling, Optical networks, Optical components, Data modeling, Model-based design, Optimization (mathematics), Switching

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Proceedings Article | 2 April 2020 Presentation

Opportunities of silicon photonics for calculation and machine learning applications (Conference Presentation)

Guangwei Cong, Noritsugu Yamamoto, Takashi Inoue, Yuriko Maegami, Morifumi Ohno, Makoto Okano, Shu Namiki, Koji Yamada

Proceedings Volume 11364, 1136409 (2020) https://doi.org/10.1117/12.2557459

KEYWORDS: Silicon photonics, Machine learning, Neural networks, Photonics, Interferometers, Electronics, Evolutionary algorithms, Optical communications, Intelligence systems, Algorithm development

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Computing enabled by electronics has been improved so extensively as to make machine learning algorithms such as deep neural network so powerful than ever before. Data communications enabled by optics have been one of the cornerstones of the modern society built upon Internet. The rapidly increasing demands for communication bandwidth due to numerous emerging applications such as AI-based cloud computing have significantly increased the bisection bandwidth of intra-datacenter networks. This trend will necessitate the optics-electronics co-packaging on board, which can only be realized by the substantial development of integrated photonics such as silicon photonics. This opportunity, making optics and electronics so close to each other, will in turn offer a chance to reconsider building EO-hybrid computational and intelligent systems. Although optical computing and optical neural networks have been proposed since a while ago, recent demonstrations of deep neural networks implemented on silicon photonics reactivate the study of exploiting photonics for machine learning. The current program-based deep neural networks are powerful, but consume huge computational resources. Suppose that just optical propagation in compact photonic chips could realize similar functions, it would greatly decrease the power and latency. Even though the scalability and the integration of nonlinear activation functions on photonic chips are still challenging, for some applications such as classifier and digit recognition, photonics systems could be viable and beneficial from such aspects. This talk will introduce our efforts to develop the topology concepts, algorithms, and applications in order to implement silicon photonics for calculation and machine learning applications. First, a high-bit reconfigurable DAC based on generic photonic circuits will be presented. Second, without using any nonlinear activation functions or building deep neural networks, we demonstrate a photonic classifier based on only linear optical components. At last, we will show several ways of implementing silicon photonic circuit to recognize digits.

Proceedings Article | 11 March 2020 Paper

Silicon-photonic matrix switches and control technologies to accelerate switching speed

Hiroyuki Matsuura, Keijiro Suzuki, Ryotaro Konoike, Kazuhiro Ikeda, Hitoshi Kawashima, Shu Namiki

Proceedings Volume 11331, 113310Q (2020) https://doi.org/10.1117/12.2552914

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Optical devices based on silicon photonic technology are very important as supporting current and future communication systems in terms of their scale of integration and productivity. Although various devices have been proposed and realized using silicon photonics technology, this paper describes an optical path switch combining a large number of 2×2-unit-switches loaded with electrical heaters on a Mach-Zehnder interferometer (MZI). We have been developed 8×8 and 32×32 optical matrix switches, which employ a path-independent-insertion-loss (PILOSS) configuration that has a feature of the same device count on the any path of the connection. The PILOSS structure has a feature of Strictly-nonblocking, which can connect any input port to any output port without changing existing connections when making a new connection. Each heater of the optical switch is driven by pulse-width-modulation (PWM) generated by a Field Programmable Gate Array (FPGA). The calibration of the pulse width according to the 2×2-unit switch state (Cross or Bar) is performed on all of the MZIs in advance, and the values are stored in a table of the FPGA. Separately, Cross / Bar state tables corresponding to the connection pattern of the optical input port and output port are prepared, and the pulse width switching according to the state table is simultaneously performed based on a switching command from the upper layer controller. It takes a certain amount of time to change the heater temperature of the MZI arm for switching. However, it is possible to shorten the switching time by applying a signal named “Turbo pulse” for a short term at the transition. When the temperature is raised by the heater, the switching can be speeded-up by applying a continuous high-level voltage to the heater temporarily. Even in the case of the temperature drops, the switching time can be accelerated by applying a continuous high-level voltage to the heater on the other arm of the MZI. The switching time, which was actually 30μs without Turbo pulse, could be reduced to 2.5 μs with Turbo pulse. The fabricated silicon photonics switch chip was mounted to the chip-carrier, assembled on a printed circuit board, and housed in a 19-inch wide 1-rack unit (RU) height blade. In addition to measuring the various characteristics of the device in our laboratory, it has also been installed and operated at the telecommunication carrier's collocation space to confirm long-term operation in the field. This shows that the technology related to the large-scale silicon photonics devices shown here can be adopted to practical use.

Proceedings Article | 9 March 2020 Presentation

Compact and large-port-count silicon photonics switches (Conference Presentation)

Kazuhiro Ikeda, Keijiro Suzuki, Ryotaro Konoike, Shu Namiki, Hitoshi Kawashima

Proceedings Volume 11284, 112841Y (2020) https://doi.org/10.1117/12.2544092

KEYWORDS: Silicon photonics, Switches, Optical switching, Data communications, Packet switching, Fast packet switching

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Proceedings Article | 28 January 2017 Paper

Toward exa-scale optical circuit switch interconnect networks for future datacenter/HPC

Kiyo Ishii, Takashi Inoue, Shu Namiki

Proceedings Volume 10131, 1013105 (2017) https://doi.org/10.1117/12.2250796

KEYWORDS: Optical switching, Wavelength division multiplexing, Light sources, Switches, Optical networks, Silicon photonics, Optical circuits, Integrated optics, Optical amplifiers, Switching

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Proceedings Article | 7 March 2016 Paper

Demonstration of 720x720 optical fast circuit switch for intra-datacenter networks

Koh Ueda, Yojiro Mori, Hiroshi Hasegawa, Hiroyuki Matsuura, Kiyo Ishii, Haruhiko Kuwatsuka, Shu Namiki, Ken-ichi Sato

Proceedings Volume 9775, 97750J (2016) https://doi.org/10.1117/12.2211998

KEYWORDS: Optical switching, Switches, Switching, Integrated optics, Optical circuits, Optical amplifiers, Laser development, Network architectures, Circuit switching, Optical networks, Tunable lasers, Fiber amplifiers, Signal attenuation

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Proceedings Article | 5 February 2013 Paper

Energy consumption and traffic scaling of dynamic optical path networks

K. Ishii, J. Kurumida, S. Namiki, T. Hasama, H. Ishikawa

Proceedings Volume 8646, 86460A (2013) https://doi.org/10.1117/12.2003591

KEYWORDS: Optical switching, Optical fibers, Switches, Optical networks, Switching, Optical amplifiers, Energy efficiency, Integrated optics, Control systems, Network architectures

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Proceedings Article | 29 November 2011 Paper

Parametric tunable dispersion compensator: distinctive features and practical issues

Ken Tanizawa, Junya Kurumida, Takayuki Kurosu, Shu Namiki

Proceedings Volume 8307, 83070S (2011) https://doi.org/10.1117/12.902827

KEYWORDS: Dispersion, Switching, Polarization, Terahertz radiation, Optical fibers, Laser development, Video, Optical networks, Transmitters, Receivers

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Proceedings Article | 26 January 2009 Paper

Optical LAN technologies for the ultra-high definition video era

S. Namiki, H. Onaka, T. Ikeuchi, K. Oyamada, K. Morito, A. Sugitatsu, H. Ishikawa, T. Asami

Proceedings Volume 7235, 723505 (2009) https://doi.org/10.1117/12.816471

KEYWORDS: Local area networks, Video, Ultrafast phenomena, Integrated optics, Interfaces, Wavelength division multiplexing, Waveguides, Optical networks, Transceivers, Switching

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Proceedings Article | 6 December 2005 Paper

Ultra short pulse generation and reshaping using highly nonlinear fibers

S. Matsushita, S. Namiki, T. Inoue, A. Oguri, T. Akutsu, J. Shinozaki, Y. Ozeki, S. Takasaka, K. Igarashi, M. Sakano, T. Yagi

Proceedings Volume 6019, 60191R (2005) https://doi.org/10.1117/12.636549

KEYWORDS: Solitons, Optical fibers, Single mode fibers, Picosecond phenomena, Light sources, Optical amplifiers, Nonlinear optics, Pulsed laser operation, Raman spectroscopy, Signal generators

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Proceedings Article | 6 December 2005 Paper

Photonic network R and D activities in Japan

Ken-ichi Kitayama, Tetsuya Miki, Toshio Morioka, Hideaki Tsushima, Masafumi Koga, Kazuyuki Mori, Soichiro Araki, Ken-ichi Sato, Hiroshi Onaka, Shu Namiki, Tomonori Aovama

Proceedings Volume 6022, 60221M (2005) https://doi.org/10.1117/12.635576

KEYWORDS: Networks, Switching, Network architectures, Wavelength division multiplexing, Optical networks, Ultrafast phenomena, Optical switching, Dispersion, Forward error correction, Broadband telecommunications

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Proceedings Article | 11 July 2002 Paper

Raman amplifier for WDM communication

Yoshihiro Emori, Shu Namiki

Proceedings Volume 4870, (2002) https://doi.org/10.1117/12.475531

KEYWORDS: Raman spectroscopy, Optical amplifiers, Fiber amplifiers, Polarization, Laser development, Amplifiers, Wavelength division multiplexing, Fiber Bragg gratings, Semiconductor lasers, Superposition

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Proceedings Article | 30 July 2001 Paper

Optical fiber amplifier technologies for next-generation WDM transmissions

Shu Namiki, Misao Sakano

Proceedings Volume 4532, (2001) https://doi.org/10.1117/12.436026

KEYWORDS: Optical amplifiers, Fiber amplifiers, Terahertz radiation, Wavelength division multiplexing, Erbium, Raman spectroscopy, Ions, Optical fibers, Ytterbium, Internet

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Showing 5 of 13 publications

Conference Committee Involvement (1)

Optical Metro Networks and Short-Haul Systems V

5 February 2013 | San Francisco, California, United States

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