26 February 2014

IBM sets record speed of 64Gb/s for data transmission over multimode optical fiber

IBM has set a new speed record for data transmission over multimode optical fiber (which is typically used to connect nearby computers within a single building or on a campus). The researchers reckon that the achievement demonstrated that the standard, existing technology for sending data over short distances should be able to meet the growing needs of servers, data centers and supercomputers through to the end of this decade.

By sending data at a rate of 64Gb/s over a cable 57m long using a vertical-cavity surface-emitting laser (VCSEL), the researchers achieved a rate that was about 14% faster than the previous record and about 2.5 times faster than the capabilities of existing typical commercial technology, it is reckoned.

To send the data, standard non-return-to-zero (NRZ) modulation was used. “Others have thought that this modulation would not allow for transfer rates much faster than 32Gb/s,” says Dan Kuchta of the IBM T.J. Watson Research Center in New York. Many thought that achieving higher transmission rates would require turning to more complex types of modulation, such as pulse-amplitude modulation-4 (PAM-4).