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We propose a multiple-input-multiple-output (M $\times$ N) optical switch with the same optical system as that used for a single-input-multiple-output (1 $\times$ N) switch based on a liquid crystal on silicon (LCOS). The proposed M $\times$ N switch can route multiple signals simultaneously from different plural inputs to plural outputs, which is called multipole multithrow (MPMT). In addition, our switch configuration can multiply an MPMT switch due to its multicast capacity by beam splitting with holographic phase modulation on the LCOS. We demonstrate a two-degree ROADM using our proposed 4 $\times$ 4 wavelength selective switch. The experimental results show that a two-degree ROADM node can be realized by using this switch. The increase in the insertion loss caused by the MPMT switching function is 3 dB due to beam splitting and 3–4.1 dB due to imperfections in the holographic phase modulations. The maximum port crosstalk (XT) is −20.0 dB. [ABSTRACT FROM PUBLISHER]

\REBa2\Cu3\Ox (REBCO, RE = rare earth) coated conductors are expected to show high performance for superconducting applications because of their high current density and high mechanical strength. Fujikura has developed REBCO coated conductor over 570 A/cm width at 77 K, self field with over 800 m length. In addition, we have succeeded in developing a 5 T cryocooled REBCO magnet with a stored energy of 426 kJ. The magnet is composed of 24 pancake coils with an inner diameter of 260 mm, and the total length of the REBCO coated conductors is approximately 7.2 km. We confirmed that the REBCO magnet could be excited up to 5 T for 720 min 9 months after the fabrication of the magnet. It is important to validate the long-term operation test results of the REBCO magnets with larger diameters in order to use these conductors in practical superconducting applications. On the other hand, we have fabricated and evaluated a model magnet before we fabricated a 426 kJ cryocooled magnet. The model magnet is composed of 6 REBCO pancake coils and 18 “dummy coils” with an inner diameter of 260 mm and an outer diameter of 515 mm. The model magnet is about the same size and shape as the 426 kJ cryocooled magnet. We have confirmed that the calculated critical current (Ic) of the top pancake coil of the model magnet was in good agreement with the measured coil Ic from 30 to 77 K under the conduction-cooled conditions. In addition, we have evaluated the thermal runaway behavior of the model magnet under the conduction-cooled conditions. As a result, we have confirmed that the model magnet with a 0.3-mm-thick copper stabilizer had sufficient time to ramp down without degradation at 361 A transport current after the detected normal transition. [ABSTRACT FROM PUBLISHER]

REBCO coated conductors are expected high performance in superconducting applications because of their high current density and high mechanical strength. However, in order to use these conductors in superconducting applications, a technique is required for fabricating impregnated REBCO coils without degradation.In this work, we fabricated six pancake coils without degradation using wounded REBCO coated conductors. These conductors were laminated with a copper tape as a stabilizer, and were fabricated by the IBAD/PLD method. In addition, we evaluated the V-I characteristics and n-values of the coils in liquid nitrogen and compared the calculated and measured values for the critical current (Ic) of the REBCO coated conductors. The measured Ic of the coils were in good agreement with the calculated ones. Furthermore, we fabricated a stacked coil using an approximately 190 m long REBCO coated conductor and evaluated the stability of the stacked coil at 77, 60 and 50 K under conduction-cooled condition. The thermal runaway current of the stacked coil was 166.4 A, and the central magnetic field was 1.27 T at 50 K. [ABSTRACT FROM PUBLISHER]

As part of the basic research for the improvement of the electromagnetic environment, the present study has developed a ferrite plate having orientation characteristics. To exhibit the orientation characteristics of a plane wave, a slit was cut on the surface of the ferrite plate. The values of the radio frequency (RF) magnetic shielding degree SDHH when holding the slit horizontal to the ground, in the frequency region of 1 MHz (43 dB) to 200 MHz (8 dB), decreased with frequency. The value of RF magnetic shielding degree SDHP when holding the slit perpendicular indicated an average value of 20 dB in this frequency region. Namely, the values of the difference, SDHH - SDHP, indicated an average value of 13 dB as the orientation characteristics. The orientation characteristics of the ferrite plate, however, displayed no orientation characteristics in the frequency region of 200 MHz to 3 GHz. Therefore, in order to improve the orientation characteristics in this frequency region, a compound plate was formed by the superposition of a slit carbon plate over the slit ferrite plate. The values of the difference, SDHH - SDHP, for the compound plate were then improved by approximately 35 dB in the frequency region from 1 MHz to 3 GHz. Experimental results revealed several orientation characteristics of the compound, slit ferrite and carbon plates. [ABSTRACT FROM AUTHOR]