Kazuhide Nakajima

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We achieved high-speed wavelength division multiplexing (WDM) transmission in the visible to infrared region over a 1 km photonic crystal fiber (PCF). We realized ultra-wide and high-speed WDM transmission using six wavelengths in the 658 to 1550 nm wavelength range, which corresponds to a frequency bandwidth of 263THz. We demonstrated WDM transmission of(More)
We investigated the inter-core differential mode delay (DMD) characteristic of a weakly-coupled homogeneous multi-core fiber with a view to utilizing inter-core crosstalk compensation with MIMO processing. We confirmed experimentally that the bend induced inter-core DMD is lower than the simulated results, which we expected owing to the twist of the fiber.(More)
We experimentally investigate the modal dependence of the guided-acoustic wave Brillouin scattering (GAWBS) characteristics in a few-mode fiber (FMF). We clarify that launching higher-order modes into FMF induces different peak frequencies from those of single-mode fiber (SMF) in the GAWBS spectrum and that the GAWBS spectrum strongly depends on the mode(More)
We describe the dopant dependence of Raman gain in germanium- and fluorine-doped optical fibers. We clarify, both theoretically and experimentally, the effective Raman gain characteristic in an optical fiber, which is closely related to the fiber's refractive-index profile and electromagnetic field profile. We also show that this experimentally determined(More)
The paper presents ultra-high-capacity transmission technologies based on multi-core space-division-multiplexing. In order to realize high-capacity multi-core fiber (MCF) transmission, investigation of low crosstalk fiber and connection technology is important, and high-density signal generation using multilevel modulation and crosstalk management are also(More)
We describe the guided acoustic-wave Brillouin scattering (GAWBS) characteristics of hole-assisted fiber (HAF). We clarify numerically and experimentally that the GAWBS spectrum corresponding to a particular acoustic mode is observed for HAF and that the efficiency for that mode can be controlled simply by designing the air-hole size and position. We also(More)