Tokyo: Researchers have developed a terahertz (THz) transmitter capable of transmitting digital data at a rate 10 times or more faster than that offered by the fifth-generation mobile networks (5G) expected to appear around 2020. The terahertz transmitter could make it possible for the whole content on a DVD (digital versatile disk) to be transferred in a fraction of a second, according to the research scheduled to be presented at the International Solid-State Circuits Conference (ISSCC) 2017 being held from February 5-9 in San Francisco, California.

The terahertz band is a new and vast frequency resource expected to be used for future ultrahigh-speed wireless communications.  “Terahertz could offer ultrahigh-speed links to satellites as well, which can only be wireless. That could, in turn, significantly boost in-flight network connection speeds, for example. Other possible applications include fast download from contents servers to mobile devices and ultrafast wireless links between base stations,” said one of the researchers Minoru Fujishima, Professor at Hiroshima University in Japan.

The research group has developed a transmitter that achieves a communication speed of 105 gigabits per second using the frequency range from 290 gigahertz (GHz) to 315 GHz.  This range of frequencies is currently unallocated but fall within the frequency range from 275 GHz to 450 GHz, whose usage is to be discussed at the World Radiocommunication Conference (WRC) 2019 under the International Telecommunication Union Radiocommunication Section (ITU-R).  Last year, the group demonstrated that the speed of a wireless link in the 300-GHz band could be greatly enhanced by using quadrature amplitude modulation (QAM).

This year, they showed six times higher per-channel data rate, exceeding 100 gigabits per second for the first time as an integrated-circuit-based transmitter.  “This year, we developed a transmitter with 10 times higher transmission power than the previous version’s. This made the per-channel data rate above 100 Gbit/s at 300 GHz possible,” Fujishima said. “We usually talk about wireless data rates in megabits per second or gigabits per second. But we are now approaching terabits per second using a plain simple single communication channel,” Fujishima added. The research group from Hiroshima University, Japan’s National Institute of Information and Communications Technology, and Panasonic Corporation plans to further develop 300-GHz ultrahigh-speed wireless circuits.