Ghent University and Imec

The Photonics Research Group

Who are we? Ghent University and imec The Photonics Research Group is a 65-person strong group at the faculty The Photonics Research Group is part of the department of of engineering of Ghent University. The group is headed by a team of four Information Technology (INTEC), and as such not only a research UGent professors: Roel Baets, Geert Morthier, Dries Van Thourhout and group of the university, but also an associated lab of imec, one of the imec Peter Bienstman, and has steadily grown to about 10 post-docs, 40 PhD world-leading research institutes for microelectronics and students and an administrative and technical support staff of 8. nanotechnology, located in Leuven, Belgium

The group focuses on research in photonic integration (“optical chips”), As such, the group has access to imec’s silicon technology, using it covering the vertical field from the technologies for making them, where as a platform to build photonic integrated circuits. Also, the group possible based on silicon, all the way up the applications, mainly in participates in many collaborative projects under the umbrella of communication, sensing and medical diagnostics. imec. Photonic integration Silicon Photonics Photonic integrated circuits integrate many optical functions on a chip. The Photonics Research Group is a pioneering group in silicon Just like in electronics, this allows more complex functionality, while at the photonics, where the power of silicon electronics manufacturing same time the integration can reduce the overall cost, by reducing technology is leveraged to make optical chips. The close relation with packaging needs and relying on wafer-scale semiconductor fabrication imec proves invaluable, resulting in the first demonstration of silicon processes. photonic wires made with industrial tools.

Like in electronics, we also aim to reduce the footprint of photonic Over the past decade, the group has built a strong portfolio of integrated circuits by going to an ever smaller scale. In photonics, this can passive silicon photonic circuit blocks, such as low-loss be done by using a high refractive index contrast, confining light in waveguides, grating couplers for fiber-chip interfaces, ring filters, submicron structures. This effectively leads to nanophotonics, where compact arrayed waveguide gratings. Also, passive functionalities light can be manipulated on wavelength scale, for instance in photonic are now being complemented by active signal modulation, crystals. However, this requires accurate fabrication technology to make integrated thermal tuning and integration with electronics through (a) the optical circuits with nanometer precision. imec’s 3D integration technology. contact for heater laser top contact ring heater made of IIIV

Tunnel Quantum junction well bottom Top metal contact

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Disk Bottom metal Research Themes Heterogeneous Integration (b) 3 heater (c) SiO2 Historically, the Photonics Research Group has always been oriented Silicon photonics offers a road to large-scale integration, as well as 2 Lateral Au contact towards optical communications, and is still working on solutions for volume manufacturing. However, silicon is a poor material for active 1 Au Au SOI wg. microdisk BCB BCB optical interconnects, access networks and all-optical digital optical functions (light generation and detection). Therefore, the 0 III-V -1 photonics. Today we are also exploring the potential of integrated Photonics Research Group explores the integration of new SiO2 Fiber photonics for sensing applications, with successful demonstrations of materials onto silicon. -2 -3 strain sensors, gas sensors as well as biosensors, including sample Si Si wg. -4 delivery technology such as microfluidics. This technology is further The main material group for this is III-V semiconductors, which are Grating coupler Microdisk laser extended towards spectroscopic analysis for medical diagnostics. bonded using onto the silicon waveguide circuits using an adhesive 0 2 4 6 8 10 layer. We have demonstrated efficient (micro)lasers, amplifiers as Active photonics integrated circuits can also be used for advanced optical well as photodetectors. IR Camera signal processing, including signal regeneration, optical memory readout functions (flip-flops). The dynamics of photonic components are also Also, more exotic materials are explored, such as IV-VI nanocrystals microfluidics applied to implement reservoir computing systems for advanced pattern for light emission, liquid crystals, nonlinear overcladdings, Tunable recognition. We also have limited but highly focused activities in of solar magneto-optic materials for optical isolators, and polymer Laser beam cells, optical MEMS and optomechanics. for thermal compensation. illumination overcladdings Receptor protein spots Grating couplers Infrastructure Projects Grating In the Ghent University clean rooms at the Technology campus in The Photonics Research Group is involved in over 15 collaborative couplers Zwijnaarde we have process technology for III-V materials, microfluidics, research projects, including internal Ghent University projects, nanoscale patterning using a state-of-the art focused ion beam writer, regional and national projects as well as several high-profile and wafer-level measurement facilities. European projects. Its unique expertise and access to world-class silicon technology makes the photonics research a key player in Additional measurement facilities are located in the city-center labs in many consortia. There are also several bilateral collaborations with the Technicum building, with setups for passive and active chip other research groups and industrial partners. characterisation, as well as automatic bit-error-rate measurements. The Photonics Research Group is also supported by a Methusalem Also, the group has a large toolset of modelling and design tools, with a structural funding grant of the Flemish regional government, to further strong mix of commercial and in-house software, backed up by distributed expand the research into smart photonic chips as an enabler for computing power, including access to the Flemish supercomputing grid. sustainable development and for health care.

Education Output and Valorisation Ghent University (UGent) jointly with the Vrije Universiteit Brussel (VUB) The Photonics Research Group publishes over 40 peer-reviewed offers three Master of Science programs in Photonics, all based on the journal papers and nearly 100 conference papers per year, with same set of basic and advanced photonics courses. usually around 10 invited papers. Some of our recent high impact publications include

The Master in de Ingenieurswetenschappen: Fotonica is a Dutch • D. Van Thourhout and Joris Roels, Optomechanical device actuation through the optical gradient force, taught two-year program and leads to a joint degree from UGent and Nature Photonics, Apr.2010 • L. Liu et al, An ultra-small, low-power, all-optical flip-flop memory on a silicon chip, Nature Photonics, Feb. 2010. VUB. Students study either in Ghent or in Brussels upon their own choice. • J. Roels et al., Tunable optical forces between nanophotonic waveguides,Nature Nanotechnology, Jul 2009 • C. Koos et al., All-optical high-speed signal processing with silicon-organic hybrid slot waveguides, Nature Photonics, Mar 2009 The Master of Photonics Science and Engineering is an English taught Journal publications by year two-year program and leads to a joint degree from UGent and VUB. The Photonics Research Group holds approximately 15 patents Students study both in Ghent and in Brussels in the first year and in related to photonic components and applications, with an additional 5 Ghent or Brussels (upon their own choice) in the second year. patents pending. Two patents are licensed for commercial use.

The Erasmus Mundus Master of Science in Photonics is an Work from the Photonics Research Group has already resulted in the international English-taught two-year program in collaboration with spin-off company Trinean, who develops and produces nanoliter Kungliga Tekniska Hogskolan (KTH) in Sweden, University of St Andrews spectrophotometers and consumables for the biotech market. and Heriot-Watt University, in the UK. Students study in (at least) two institutions in two different countries. The Photonics Research Group is also a key member of the Plateau Photonics Innovation Center, a valorisation cluster of Ghent University labs.