NICT has achieved a world record 40 Gigabits/s wireless transmission

The demand for broadband connection services available anywhere and anytime has been growing rapidly, because high-performance mobile terminals such as smart phones which require high-speed data transmission are gaining popularity. To meet the demand, optical fiber communications are used to provide broadband connections between fixed points, but they are not completely suitable for wireless communication technologies of mobile terminals when it comes to convenience. For example, regarding transmission speed, wireless systems are much slower than optical fiber systems: the bit rate of IEEE 802.11n is 0.3 Gbps because available radio wave bandwidths are limited, while over 10 Gbps optical transmission is commonly used in commercial systems. The bit rate difference between optical and radio-wave systems should be reduced in order to increase satisfaction of mobile terminal users. Microwave bands are commonly used for various types of wireless systems, with most of frequency resources already occupied by existing services, whereas there are wide bands available in millimeter-wave bands.

Based on NICT’s recent outcomes: “photonic millimeter-wave source” and “high-speed and precise 16-level optical modulation”, NICT has demonstrated 40 Gbps millimeter-wave wireless transmission, using “photonic to millimeter-wave conversion” newly developed by NICT and “digital signal processing” by Osaka-U. Millimeter-wave has wide-frequency resources available, however, precise and high-speed control of millimeter-waves is not easily attained because the frequency is much higher than in microwave bands. In our experiment, we have achieved wideband signal modulation and demodulation of millimeter-waves by using optical technologies which can provide wideband operation.