Swedish Research company Acreo and leading telecom vendor Ericsson have completed a field trial, running 112 Gbit/s on a single wavelength over an 824 km installed fiber route, provided by Skanova, between Kista and Hudiksvall in Sweden. The trial demonstrated a novel solution based on electronic sub-carrier multiplexing combined with 16-QAM modulation and coherent detection, developed by Ericsson and Acreo in joint research projects directed towards increasing capacity of optical networks.
A 100G upgrade scenario was tested by connecting the dual-polarization 112 Gbit/s wavelength to an existing 10G engineered DWDM system, operated by Acreo, without touching any of the optical amplifiers or dispersion compensation modules. The fiber link connects Kista to Hudiksvall where the fiber was looped back for a total of 12 spans.
The tests involved broad-band radio technology to modulate and demodulate electronic sub-carriers, which allows operation at low symbol rates compared to single-carrier solutions, simplifying A/D-converters and digital signal processing (DSP). Two sub-carriers were modulated onto each orthogonal polarization of a single transmitter laser and detected using a single local oscillator laser in the coherent receiver. By leveraging on electronics integration the number and complexity of optical components can be reduced, thereby saving cost.
For this trial, offline DSP algorithms implemented by Acreo were employed. “Our tests show the feasibility of spectrally efficient 16-QAM modulation together with coherent detection and DSP for mitigating transmission impairments under realistic conditions”, said Jonas Mårtensson, Project Manager at Acreo.
The funding for Acreo’s participation in research projects leading to these results was partly provided by Sweden’s innovation agency VINNOVA.
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Acreo is one of Europe's top research companies providing breaking edge results within the field of electronics, optics and communication technologies. Turning academic research into commercial products, Acreo offers value-adding technology solutions for growth and competitiveness in industry and society. The types of assignments are ranging from feasibility studies, long term research projects, prototyping and small scale production, to verification and testing. Acreo also supports small and medium sized companies with technology transfer, business networks and financial advice. Acreo is part of Swedish ICT and has about 140 employees located in Kista (headquarter), Norrköping and Hudiksvall.