In this paper, a double axial gap type induction motor having a toroidal winding stator structure is proposed for the purpose of improving the torque density and efficiency of the induction machine. It consists of an axial type squirrel-cage induction rotor, and a toroidal winding stator structure suitable for armature copper loss reduction, miniaturization and a double axial gap structure. After explaining the reasons for selecting the single stator and double rotor structures, the structural design of the prototype and the experimental setup will be reported. The slip-vs.-torque characteristics are measured to clarify the drive characteristics, and the features of the proposed motor used soft magnetic composites are discussed by the equivalent circuit method. As a result, it was experimentally clarified that the double axial gap type induction motor with soft magnetic composites has a high slip torque characteristic and the reduction of the excitation current is an important issue for improving the performance.

A novel system for transparent relaying and switching of terahertz (THz)-wave signals is demonstrated using a low-loss optical modulator and ultra-fast tunable laser. A 32-Gb/s OFDM signal was transmitted over a switchable fiber–THz–fiber–THz system in the 285-GHz band.

To achieve wavelength division multiplexing of optical communications for short distances, we have theoretically investigated a photonic crystal waveguide we call an orthogonal lattice waveguide (OLW), which may have a communication wavelength bandwidth of about 20 nm. In this paper, we fabricate CirD laser structures with air cladding layers and OLWs of different cavity radii. We confirm that the light emitted from the OLW is the light generated in the cavity. OLW has a wavelength bandwidth of about 20 nm, which agrees with the results of our previous theoretical study. The wavelength shift is about 4 nm when the radius of the circular defect cavity increases by 0.01 a, where a is the lattice constant.

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