Photonic chip transmits 2 million HD channels at the same time
Image above – Frequency (circular) combs can be seen on the surface of the photonic chip. [Image: V. Brasch (LPQM / EPFL)]
This tiny photonic chip, ready to be integrated into fiber-optic communications systems, has achieved a data rate of 55 terabits per second at a distance of 75 km.
The great novelty is that it works by solitons, a mixture of waves and complex particles until recently seen as very interesting curiosities but without immediate practical applications.
That has changed when Pablo Palomo and his colleagues from the Federal Polytechnic School of Lausanne (Switzerland) and the Karlsruhe Institute of Technology (Germany) have dropped the frustrated approach of attempting to trigger pulses of solitons through an optical fiber. Placed first to circulate continuously in a ring micro-resonator, which created an optical frequency comb.
Overlapping two of these frequency combs, the team found that a massive transfer of data could be done in parallel using 179 different optical channels – each with a color – reaching a record rate of 50 terabits per second.
Two million HD channels
Optical frequency combos, which earned the 2005 Nobel Prize in Physics for John Hall and Theodor W. Hänsch, consist of a multiplicity of neighboring spectral lines, aligned in a regular grid. More recently, the invention of the so-called Kerr frequency combs, characterized by wide optical bands and inter-line spacing that are optimal for communications, have made this photonic device subject to intense research for practical application.
As now shown, each spectral line can be used to transmit a data line, reaching 179 channels in this prototype.
“This equates to more than two million HD TV channels or more than five billion phone calls,” said Professor Christian Koos, coordinator of the team. “It’s the highest transfer rate ever achieved using a chip-like frequency comb.”
In addition to speed and bandwidth, photonic chip
Sources: Microresonator solitons for massively parallel coherent optical communications
Pablo Marin-Palomo, Juned N. Kemal, Maxim Karpov, Arne Kordts, Joerg Pfeifle, Martin H. P. Pfeiffer, Philipp Trocha, Stefan Wolf, Victor Brasch, Miles H. Anderson, Ralf Rosenberger, Kovendhan Vijayan, Wolfgang Freude, Tobias J. Kippenberg, Christian Koos