Katsuhiro Shimizu

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A novel all-optical modulation format conversion from non-return-to-zero on-off-keying (NRZ-OOK) to return-to-zero quadrature-phase-shift-keying (RZ-QPSK) is proposed and experimentally demonstrated. The proposed format conversion scheme is based on parallel Mach-Zehnder interferometric (MZI) OOK/binary-PSK (BPSK) converters, consisting of integrated(More)
We have obtained 40 dB of internal (on-off) conversion gain and a sub-4-dB noise figure (NF) with a continuous-wave (cw) fiber optical parametric wavelength converter. To our knowledge, this is the lowest NF reported for any cw wavelength converter. We have also investigated the properties of NF versus signal input power and pump power.
For the satellite tokamak JT-60 Super Advanced (JT-60SA), a divertor Thomson scattering measurement system is planning to be installed. In this study, we improved the design of the collection optics based on the previous one, in which it was found that the solid angle of the collection optics became very small, mainly because of poor accessibility to the(More)
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