Researchers at Chalmers University of Technology in Sweden have developed a 140 GHz transmitter chip capable of a transmission rate of 40 Gbps.
The transmitter device is implemented in indium phosphide and contains an I-Q modulator, a 3-stage amplifier, and a x3 frequency multiplier for the local oscillator.
“We have designed circuits for signals at 140 Gigahertz, where we have a large bandwidth. In laboratory testing, we have achieved a transmission rate of 40 Gigabit data per second, which is twice as fast as the previous world record at a comparable frequency,” says Herbert Zirath, who is a professor in high speed electronics at Chalmers. He is also employed by Ericsson Research on a part-time basis.
http://www.chalmers.se/en/departments/mc2/news/Pages/World-record-in-data-transmission-with-smart-circuits.aspx