Optical technologies are the enabling technologies for our communication networks. The ever increasing demand of bandwidth boosts new developments in a wide range of optical components, optical transmission systems and optical networks. This also leads to short innovation cycles and therefore a high demand in research work in the fields mentioned above. During the last few years the integration of electronic and optical signal processing and conditioning can be observed. For example forward error correction methods, digital signal processing for equalization are important actual topics of this field. But also e.g. the implementation of advanced multilevel modulation formats optical decoding devices and research in the field of flexible dynamic network issues are important aspects at the field of optics.

Future ultra high capacity systems and networks also will have to focus on technologies for optical signal regeneration, optical processing of multilevel phase and amplitude encoded signals, optimized concepts for mixed optical and electronic signal equalization techniques, new concepts for capacity increase in optical networks and of course energy efficient communication system designs.

In addition to these backbone network related topics, optical transmission technologies are also important in short distance systems like in house applications and automotive applications or at even shorter distance in data centres and in inter and intra circuit data transfer.

Besides the classical optical communication applications, optical quantum communication is investigated in basic research and also evokes some interest in different areas of application.

The research activities in SAOT so far concentrated on the topics related to next generation optical communication systems. Here optical regeneration concepts for phase encoded signals were investigated, concepts for signal power transient suppression in dynamically switched optical communication networks were developed, signal noise interaction during fiber propagation was studied, concepts for compensation of signal distortions by digital backward propagation and electronic equalization were studied, and finally work on few mode and multi mode fibber propagation has been started. In the field of quantum communication the activities range from quantum information theory and optical quantum information theory to quantum information processing.

Ongoing and new future research work and education is planned in the fields given in the following paragraphs.

High capacity transmission systems

The research program for the next future in high capacity transmission systems will concentrate on the demands of actual and next generation optical transmission systems. Here we plan to further develop the various schemes of optical signal regeneration. The concepts to be investigated will also include e.g. phase sensitive amplification and new concepts for the still open question for regeneration of wavelength division multiplexing signals.  A special emphasis will also be put on the regeneration of multilevel phase and amplitude encoded signals like quadrature amplitude modulation (QAM)

Due to the fact that new system concepts include a significant amount of electronic equalization these concepts have to be included in the next period of research. The equalization of linear fiber propagation effects has developed quite well during the last few years but mitigation of nonlinear propagation effects is still a topic of research. The research started in this field of digital backward propagation will be continued in order to explore the potential of various methods and also to take complexity restrictions in future hardware implementations into account.

The development of a setup behaving like a material with negative Kerr nonlinearity opens the door for future investigation of new concepts of link designs including this new type of devices. Here also the interaction with receiver side electronic compensation techniques has to be considered. This is important e.g. for optimum phase noise compensation.

In order to raise the transmission capacity, multiple input multiple output (MIMO) system concepts based on few mode fibers are discussed. Based on some first theoretical investigations, this topic has to be treated in more detail for example in the context of launching conditions, launching devices, propagation effects, channel separation and suitable signal processing.


Short range systems

Besides the quite well established concepts for multimode transmission using polymer optical fibers  optical transmission concepts for short range transmission are attractive candidates to overcome the challenges of ultra high data rate transport within e.g. data centers, systems or even chips. Integrated microphotonics and optical interconnect will gain in importance over the next years. Within the SAOT the potential to launch research activities in this field have to be considered as also here highly interdisciplinary aspects characterize this field. 

Advanced optical components

The planned activities in the context of few mode fiber transmission raise the question for optical components with a sufficient amount of modal selectivity. For example the inscription of fiber Bragg gratings in few mode fibers and the study of their usability for modal selection or modal filtering would clearly support the modal selective concepts in future. This devices are at the time being investigated in terms of their fabrication concepts, their usage in fiber sensors and fiber lasers. The broadening of the field of application will produce a lot of benefit in the scientific field but also for the overall goals of SAOT.

Quantum Optics

In addition to the classical optical communication and signal processing, the use of the quantum nature of light especially for ultra short soliton pulses has potential for future applications. Thus the behaviour of devices and subsystems for non-classical light has to be studied to explore the capability of usage in these new types of systems. Especially research on quantum information processing, quantum key distribution, quantum cryptography and  quantum protocols is of high importance in this context.