Our objective is to develop next-generation, optical-communications system technologies addressing new technology fields such as ultra-high-speed digital signal processing and space-division-multiplexing optical communication, and to establish the following four elemental technologies essential to a petabit-class scalable optical network that can support increasing capacity of traffic generated by the expansion of cloud services and the spread of smartphones. We study mainly about these four fundamental technological fields by coordinating key components and materials technology from a system viewpoint. We also study to apply these core technologies to new application fields such as future optical/wireless converged networks.
We will study large-scale digital signal processing technologies such as multi-input and multi-output (MIMO) technology to maximally utilize the nature of light waves (coherency) for achieving a dramatic improvement in transmission efficiency.
To achieve a drastic improvement in system performance, we will study system and component technologies to reduce noise and waveform distortion occurring in conventional optical amplifier systems. Specifically, we will apply photonic pre-signal-processing technology such as coherent amplification based on optical parametric effects by complementarily using with existing erbium-doped fiber amplifier (EDFA) technology.
We will study system and component technologies for enhancing capacity by overcoming the transmission-capacity limitations of existing single-mode optical fiber (saturation of spectrum efficiency due to the nonlinear Shannon limit, optical input power limits due to the fiber fuse phenomenon).
We will study integration technologies for photonics and electronics convergence with the aim of achieving a drastic reduction in the size and power consumption of systems used to configure the future scalable, large-capacity optical network.
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Figure 1: Achieving a scalable, large-capacity optical network
1) World Record One Petabit per Second Fiber Transmission over 50-km: Equivalent to Sending 5,000 HDTV Videos per Second over a Single Fiber http://www.ntt.co.jp/news2012/1209e/120920a.html
2) New Amplifier Increases Optical Fiber Transmission Capacity by more than Four Times (Nikkei Sangyo Shimbun, June 28, 2011) (in Japanese)
1) Y. Miyamoto et al.: 鉄patial-multiplexing Optical Transmission Technology for Large-capacity, Long-distance Transmission,・IEICE Transactions, Special Section, Vol. 97, No. 2, pp. 113-118, 2014. (in Japanese)
2) Y. Miyamoto: 鉄patial-multiplexing Optical Communications Technology for Exceeding Petabit Capacities,・Special Issue, OPTRONICS No. 6, pp. 72-76, 2013. (in Japanese)
1) T. Mizuno, T. Kobayashi, H. Takara, A. Sano, H. Kawakami, T. Nakagawa, Y. Miyamoto, Y. Abe, T. Goh, M. Oguma, T. Sakamoto, Y. Sasaki, I. Ishida, K. Takenaga, S. Matsuo, K. Saitoh, and T. Morioka, ・2-core 3-mode Dense Space Division Multiplexed Transmission over 40 km Employing Multi-carrier Signals with Parallel MIMO Equalization・ Proc. OFC2014, Th5B.2, 2014.
2) T. Kobayashi, H. Takara, A. Sano, T. Mizuno, H. Kawakami, Y. Miyamoto, K. Hiraga, Y. Abe, H. Ono, M. Wada, Y. Sasaki, I. Ishida, K. Takenaga, S. Matsuo, K. Saitoh, M. Yamada, H. Masuda, and T. Morioka, ・ﾗ344 Tb/s propagation-direction interleaved transmission over 1500-km MCF enhanced by multicarrier full electric-field digital back-propagation,・Proc. EOOC2013, PD3. E. 4, 2013.
3) M. Asobe, T. Umeki, H. Takenouchi, and Y. Miyamoto, 的n-line phase-sensitive amplifier for QPSK signal using multiple QPM LiNbO3 waveguide,・Proc. OECC2013, PD-2-3, 2013.
4) T. Umeki, O. Tadanaga, M. Asobe, Y. Miyamoto, and H. Takenouchi, 擢irst Demonstration of High-Order QAM Signal Amplification in PPLN-based Phase Sensitive Amplifier,・Proc. EOOC2013, PD1.C.5 2013.
5) H. Takara, A. Sano, T. Kobayashi, H. Kubota, H. Kawakami, A. Matsuura, Y. Miyamoto, Y. Abe, H. Ono, K. Shikama, Y. Goto, K. Tsujikawa, Y. Sasaki, I. Shiba, K. Takenaga, S. Matsuo, K. Saitoh, M. Koshiba, and T. Morioka, ・.01-Pb/s (12 SDM/22 WDM/ 456Gb/s) Crosstalk-managed Transmission with 91.4-b/s/Hz Aggregate Spectral Efficiency,・Proc. ECOC2012, Th.3.C.1, 2012.
6) A. Sano, T. Kobayashi, S. Yamanaka, A. Matsuura, H. Kawakami, Y. Miyamoto, K. Ishihara, and H. Masuda, ・02.3 Tb/s (224 x 548-Gb/s) C- and Extended L-band All Raman Transmission over 240 km using PDM-64QAM Single Carrier FDM with Digital Pilot Tone,・Proc. OFC/NFOEC2012, PDP5C.3, 2012.