There has been an increasing interest in the application of terahertz (THz) waves to broadband wireless communications. In particular, use of frequencies above 275 GHz is one of the strong concerns among radio scientists and engineers, because these frequency bands have not yet been allocated at specific active services, and there is a possibility to employ extremely large bandwidths for ultra-broadband wireless communications. Introduction of photonics technologies for signal generation, modulation and detection is effective not only to enhance the bandwidth and/or the data rate, but also to combine fiber-optic (wired) and wireless networks. This paper reviews recent progress in THz wireless communications using telecom-based photonics technologies towards 100 Gbit/s.

No abstract

InGaN single-crystal films were grown on (0001) plane sapphire substrates at 800 °C by metalorganic vapor phase epitaxy. By using such a high temperature for growth, the crystalline quality has been greatly improved. But a high nitrogen over pressure and high indium source flow rate were necessary to achieve significant indium incorporation during growth. For the first time, photoluminescence has been observed in InGaN, and near-band edge emission is seen in the photoluminescence at 77 K. From this photoluminescence, the dependence of a near-band edge emission on the indium mole fraction of InGaN has been investigated.

No abstract

No abstract