The renowned ERC Starting Grant is a special recognition of Bernhard Schrenk’s many years of research, which is among the very best in Eu- rope. At the same time, Schrenk can now expand his team in AIT’s Competence Unit Security & Communication Technologies, aided by the five-year grant for excellence from the European Research Council for young researchers in fundamental research – and as such, he can create important momentum for further developing base technologies in the field of telecommunications and information processing. This European sponsorship prize is also a very special distinction for AIT Austrian Institute of Technology as an application-oriented research and technology organisation.

Schrenk has been working with photonics at the AIT Center for Digital Safety & Security since 2013. His research interests include the fields of optical telecommunications, integrated optoelectronic circuits, quantum technology and sensor technology. Coherent detection, which is planned for optical signal detection, has already been long establis- hed in radio technology. Every very high frequency radio makes use of this detection method to select the station to be received. This method involves a signal generated far away and a local reference signal being on exactly the same wave length. This allows not only filterless selec- tion of one of several simultaneously transmitted signals, but it also provides receiving sensitivity that is at least 100 times higher and gives access to additional signal properties. “However, in photonics the pro- cedure of coherent signal detection is a very complex matter,” Schrenk explains. His research is investigating to what extent equally indepen- dent optical signals can be coordinated precisely to each other. In or- der to master this challenge, he has received the five-yearERC grant for excellence COYOTE – “Coherent Optics Everywhere: a New Dawn for Photonic Networks”.

VASTLY MORE EFFICIENT

The use of light as an information carrier for electrical signals allows the optical carrier wave to have a frequency that is increased by a fac- tor of 10,000. As a result, an inconceivable amount of up to 10 peta- bits of data can be transmitted every second through a single fibre optic. However, this can only work using coherent signal detection. Achieving this in photonics is tremendously complex. Despite the comprehensive presence of photonic networks, which transmit around 90% of data inconspicuously across distances of up to 10,000km, lots of the systems in use actually use direct signal detec- tion because of this complexity. “However, direct signal detection collects only the intensity of the light signal and is blind to other pro- perties, such as phase or polarisation. Direct signal detection thus represents a barrier for energy and cost efficiency in telecommunica- tions infrastructure and data centers,” Schrenk explains.

With his purely optical approach that avoids the weaknesses of elec- tronic methods, signals can now be synchronised directly on an opti- cal level. Even at extremely high carrier frequencies of around 190 terahertz, there are no frequency deviations. As the transmission of information is possible without additional corrections, despite cohe- rent transmission, no energy-demanding digital signal processing is required, which would also need quite a bit of band width as well. This significantly increases energy efficiency. Another advantage over direct signal transmission is that the dimensions of phase and polari- sation can also be analysed alongside light intensity in order to ensu- re scalability in relation to the data rate. As such, the optical spec- trum can be put to the best possible use.