Optical Frequency Combs Speed up Data Transmission

Optical Frequency Combs Speed Up Data Transmission

22 April 2014
German and Swiss researchers have achieved a data rate of 1.44 Tbits/s over a distance of 300 kilometers by deploying a miniaturized frequency comb as optical source. The results from the experiment could provide a leap ahead in the acceleration of data transmission in large computing centers and global communication networks, the scientists hope.
The researchers, from the Karlsruhe Institute of Technology (KIT) and Ecole Polytechnique Federale de Lausanne (EPFL), said that their tests showed for the first time that miniaturized optical frequency comb sources are appropriate to use for data transmission in the terabit range.
The data rate accomplished by the researchers corresponds to over 100 million phone calls or 500,000 high definition videos transmitted at the same time. The researchers explained this was achieved thanks to the use of an optical microresonator made of silicon nitride, where laser light was coupled through a waveguide and stored for a long time.
The researchers made use of the so-called Kerr effect achieved during the experiment owing to the high light intensity in the resonator. This allowed the team to generate a multitude of spectral lines from a single continuous-wave laser beam, thus creating a frequency comb, said Jorg Pfeifle, the scientist performing the experiment at KIT.
The technique for producing these so-called Kerr frequency combs was invented by Tobias Kippenberg, a researcher at EPFL, seven years ago. They have a large optical bandwidth and can have line spacings that successfully comply with the requirements of data transmission.