Researchers at the Technical University of Denmark (DTU) have achieved an optical transmission speed of 43 terabits per second ( 43 Tbps) using a single laser and a single fiber.
The demonstration used a new type of optical fiber (developed by NTT) that contains seven cores (glass threads) instead of the single core used in standard fiber.
DTU noted that its researchers have previously helped achieve the highest combined data transmission speed in the world—an incredible 1 petabit per second—although this involved using hundreds of lasers.
http://www.dtu.dk/english/News/Nyhed?id=bed76c33-c9da-4214-91f3-c9ed3f8a0e24