The team exploited the optical solitons circulating in silicon nitride microresonators to generate broadband optical frequency combs. By superimposing two frequency combs, the researchers achieved parallel data transmission on 179 wavelength channels at more than 50Tbit/s.
“This is equivalent to more than 5billion phone calls or more than 2million HD TV channels. It is the highest data rate ever reached using a frequency comb source in chip format,” explains KIT Professor Christian Koos.
Optical solitons are special wave packages that propagate without changing their shape. In optical communications, solitons can be used for generating frequency combs with various spectral lines, which help realise particularly efficient and compact high capacity optical communication systems. Each spectral line can be used for transmitting a separate data channel.
Microresonator soliton frequency comb sources can be used not only at the transmitter, but also at the receiver side of wavelength division multiplexing systems.
According to Prof Koos, this is an important step towards highly efficient chip-scale transceivers for future petabit networks.