Katsuhiro Shimizu

  • Citations Per Year
Learn More
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.
Integrated modeling on areas of plasma core, edge-pedestal and scrape-off-layer (SOL)-divertor progressed based on the researches in JT-60U experiments. An anomalous transport model of fast particles due to the Alfvén eigenmode is proposed in the core plasma and a new one-dimensional core transport code, which can describe the radial electric field and(More)
A model of the neutral transport in tokamaks has been developed suitable for a one-dimensional transport code, TASK/TX. The model consists of the one-dimensional diffusion equations for slow, thermal and halo neutrals, which are simultaneously solved together with two-fluid equations and Maxwell’s equation. The behavior of the slow neutrals is easily(More)
Design of the power handling for the demo tokamak reactor, SlimCS, with the fusion power of Pfus ≤ 3 GW and the exhausted power of Pout = 500 MW was investigated. First, effects of the divertor geometry of the V-shaped corner and the Ar impurity seeding on the radiation distribution and the target power loading were summarized in the simulation(More)
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)
The characteristics of the JT-60U detached divertor plasma in the SONIC simulation are investigated. With increasing mid-plane density, the electron temperature at the divertor decreases and the ion flux to the divertor plate increases. At higher densities, the temperature becomes less than 1 eV. However, rollover of the ion flux at the divertor plate,(More)
– Cover Story Mitsubishi Electric Corporation has been developing optical-access equipment as the foundation for broadband communications, along with the technologies that make such equipment possible. The photographs on the cover show some of our main products that combine to constitute a GE-PON (Gigabit Ethernet Passive Optical Network). In particular, we(More)
  • 1