Fraunhofer HHI participates in the EU project 3PEAT and achieves first promising project results

Scientists from the Fraunhofer Heinrich Hertz Institute take part in the EU-Horizon-2020 research project 3PEAT, which started with a kick-off in Athens in January 2018. The goal of the project is to develop a novel integration platform based on PolyBoard and TriPleX with low optical loss, high functionality and high integration density for applications in communications engineering and sensor technology.

The Photonic Components Department at the Fraunhofer Heinrich Hertz Institute is part of an international consortium consisting of two other research institutes (Institute of Communications and Computer Systems ICCS, and University of Twente) and six companies (Optagon Photonics, LioniX, SolMateS, Cordon Electronics Italia, Mellanox and Polytec). The consortium is coordinated by the ICCS in Athens.

One of the major objectives of the project is the development of a fully functional 3D photonic integration platform based on the use of multiple waveguide layers and vertical couplers in Fraunhofer HHI’s PolyBoard technology, as a means to disrupt the integration scale and functionality. In addition, 3PEAT will combine this novel 3D technology with the TriPleX platform from LioniX. An integrated process for the fabrication of 3D PolyBoards of Fraunhofer HHI directly on the TriPleX wafers of LioniX will be developed.

Leveraging this 3D integration platform, the 3PEAT consortium will model, design and fabricate optical switching and sensing modules. The research group Hybrid PICs at Fraunhofer HHI (Department of Photonic Components) has already achieved promising preliminary results.


The PolyBoard and TriPlex platforms being upgraded individually as part of 3PEAT, are planned to be made available as a single integration platform in the future as well. The combination of the advantages of both platforms is expected to offer new capabilities in the design and manufacturing of integrated photonic components and to open new market opportunities, addressing the customers’ specific needs by providing tailor-made solutions.

Madeleine Nuck, research assistant at Fraunhofer HHI, has developed and successfully manufactured a vertical MMI coupler with a coupling loss of just 1.0 dB. The manufacturing process optimized for 3D integration also guarantees higher precision in layer thickness control and a lateral offset below 200nm when stacking up the multilayer systems in the clean room fabrication processes.

Hauke Conradi, also a research associate at Fraunhofer HHI, has designed and manufactured the world's first polymer-based micro-optical isolator, which is enabled by the hybrid integration of a bulk Faraday rotator into the PolyBoard platform. With an isolation of more than 20 dB over 80 nm bandwidth at a peak value of 33 dB, this novel device enables the simultaneous realization of high isolation and wide bandwidth in integrated optics for the first time.

The institute is thereby focusing specifically on the promotion of young researchers: In the course of the 3PEAT project, doctorates are planned in the fields of “Photonic 3D Integration” and "Micro-optical Bank/Circulator".