Tetsuya Kobayashi
Hirosaki University
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Publication
Featured researches published by Tetsuya Kobayashi.
optical fiber communication conference | 2012
Jun Sakaguchi; Benjamin J. Puttnam; Werner Klaus; Yoshinari Awaji; N. Wada; Atsushi Kanno; Tetsuya Kawanishi; Katsunori Imamura; Harumi Inaba; Kazunori Mukasa; Ryuichi Sugizaki; Tetsuya Kobayashi; Masayuki Watanabe
A novel free-space coupling system combined with a multi-core fiber enables up-scaling to a record space-division-multiplexed (SDM) channel number of 19. We achieve 305-Tb/s transmission over 10.1 km using 19-SDM, 100-WDM PDM-QPSK signals.
Journal of Lightwave Technology | 2013
Jun Sakaguchi; Benjamin J. Puttnam; Werner Klaus; Yoshinari Awaji; Naoya Wada; Atsushi Kanno; Tetsuya Kawanishi; Katsunori Imamura; Harumi Inaba; Kazunori Mukasa; Ryuichi Sugizaki; Tetsuya Kobayashi; Masayuki Watanabe
We report record capacity data transmission at 305 Tb/s over 10.1 km, using space division multiplexing (SDM) with 19 channels. To realize such a large SDM channel number, we fabricated a trench-assisted homogeneous 19-core fiber with average intercore crosstalk of about -32 dB at 1550 nm. We also fabricated a 19-channel SDM multiplexer/demultiplexer using free-space optics with low insertion losses and low additional crosstalk. The data signal transmitted through each SDM channel was 100 wavelength division multiplexing (100 GHz spacing) 2 × 86 Gb/s polarization-division-multiplexed quadrature phase shift keying signals and the spectral efficiency was 30.5 b/s/Hz.
Optics Express | 2014
Jun Sakaguchi; Werner Klaus; Benjamin J. Puttnam; Jose Manuel Delgado Mendinueta; Yoshinari Awaji; Naoya Wada; Yukihiro Tsuchida; Koichi Maeda; Masateru Tadakuma; Katsunori Imamura; Ryuichi Sugizaki; Tetsuya Kobayashi; Yusaku Tottori; Masayuki Watanabe; R. V. Jensen
We report the development of a space division multiplexed (SDM) transmission system consisting of a 19-core fiber and 19-core Erbium-doped fiber amplifier (EDFA). A new 19-core fiber with an improved core arrangement was employed to achieve a low aggregated inter-core crosstalk of -42 dB at 1550 nm over 30 km. The EDFA uses shared free-space optics for pump beam combining and isolation, thus is SDM transparent and has some potential for cost reduction. 19.6 dB to 23.3 dB gain and 6.0 dB to 7.0 dB noise figure were obtained for each SDM channel at 1550 nm. System feasibility for SDM transmission over 1200 km was demonstrated with 100 Gb/s PDM-QPSK signals.
Journal of Lightwave Technology | 2012
Jun Sakaguchi; Yoshinari Awaji; Naoya Wada; Atsushi Kanno; Tetsuya Kawanishi; Tetsuya Hayashi; Toshiki Taru; Tetsuya Kobayashi; Masayuki Watanabe
We achieved record 109-Tb/s transmission over 16.8 km, using space division multiplexing (SDM) together with conventional multiplexing technology. 7-core SDM, 97 WDM (100-GHz spacing), 2 × 86 Gb/s PDM-QPSK signals were used. The spectral efficiency was 11.2 b/s/Hz. SDM transmission was realized using a multi-core fiber with ultra-low-crosstalk (less than -90.0 dB/km at 1550 nm) and high performance SDM MUX/DEMUX. The overall SDM crosstalk of -53 dB caused almost no penalty for the PDM-QPSK transmission.
IEEE Photonics Technology Letters | 2012
Werner Klaus; Jun Sakaguchi; Benjamin J. Puttnam; Yoshinari Awaji; Naoya Wada; Tetsuya Kobayashi; Masayuki Watanabe
In this letter, we report on coupling optics for connecting single-core single-mode fibers with multicore single-mode fibers. After a brief discussion of the options for such coupling systems, we describe our approach of using bulk optics to fabricate low-loss and low-crosstalk devices for both 7- and 19-core multicore fibers with the free-space design approach. This enables the use of the same coupling device with a variety of multicore fibers whose structural parameters differ from one sample to another. We present the results of experimental evaluations of these devices, discuss various causes of insertion loss, and analyze the coupling loss in detail.
Journal of Lightwave Technology | 2016
Jun Sakaguchi; Werner Klaus; Jose Manuel Delgado Mendinueta; Benjamin J. Puttnam; Ruben S. Luis; Yoshinari Awaji; Naoya Wada; Tetsuya Hayashi; Tetsuya Nakanishi; Tatsuhiko Watanabe; Yasuo Kokubun; Taketoshi Takahata; Tetsuya Kobayashi
We describe the design and characterization of a heterogeneous 36-core, three-mode fiber with three core types. Intercore crosstalk for LP11 modes is estimated to be below -31 dB for 5.5 km propagation at a core pitch of 34 μm. Feasibility of 108 space/mode division multiplexed transmission is investigated using free-space multiplexing/demultiplexing technologies, 40-wavelength division multiplexed, 25 GBd, 93.4-Gb/s dual-polarization QPSK signals, and coherent detection with a sparse 6 × 6 MIMO equalizer. The total transmission capacity amount to 403.7 Tb/s.
IEEE Photonics Technology Letters | 2012
Yusaku Tottori; Tetsuya Kobayashi; Masayuki Watanabe
A pair of compact optical connection modules that connect seven-core multicore fiber and seven single-mode fibers is developed. Insertion loss of <;0.6 dB, polarization-dependent loss of <;0.1 dB, and crosstalk of >;-50 dB are observed. The structure is applicable to the multicore fiber with more than seven cores.
photonics society summer topical meeting series | 2012
Werner Klaus; Jun Sakaguchi; Benjamin J. Puttnam; Yoshinari Awaji; Naoya Wada; Tetsuya Kobayashi; Masayuki Watanabe
We describe the design of low-loss and low-crosstalk free-space coupling optics for multi-core fibers and discuss in detail its experimental evaluation.
Japanese Journal of Applied Physics | 2005
Shoji Kakio; Shinji Uotani; Yasuhiko Nakagawa; Takefumi Hara; Hiromasa Ito; Takashi Iizuka; Tetsuya Kobayashi; Masayuki Watanabe
A waveguide-type acoustooptic modulator (AOM) driven by a surface acoustic wave (SAW) in a tapered crossed-channel waveguide on a 128°-rotated Y-cut LiNbO3 substrate has been proposed for an optical wavelength of 1.55 µm. In this study, to clarify the conditions for a higher diffraction efficiency and a lower driving power, the diffraction properties of the waveguide-type AOM were measured and simulated. First, an AOM with an AO interaction region length of 3 mm was fabricated and the diffraction efficiency of 65% was obtained. Next, the measured values of the SAW power required for 100% diffraction (P100) for the driving frequencies of 125 MHz and 200 MHz were found to be in agreement with the calculated P100, which shows that there is an optimum driving frequency. Furthermore, optical frequency domain ranging using a frequency-shifted-feedback fiber laser with the waveguide-type AOM was demonstrated. Finally, the diffraction properties of the waveguide-type AOM are simulated using a beam-propagation method (BPM) and compared with the experimental results.
optical fiber communication conference | 2011
Jun Sakaguchi; Yoshinari Awaji; Naoya Wada; Tetsuya Hayashi; Takuji Nagashima; Tetsuya Kobayashi; Masayuki Watanabe
Propagation characteristics of seven-core fiber were investigated for multiplexed signals of spatial-division and wavelength-division. Effect of chromatic dispersion and inter-core crosstalk were evaluated for 5-km fiber by using 10-Gbit/s channels.
Collaboration
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National Institute of Information and Communications Technology
View shared research outputsNational Institute of Information and Communications Technology
View shared research outputsNational Institute of Information and Communications Technology
View shared research outputs