Light: the Essential Ingredient for Future Technology

The exponential increase in data traffic is becoming unsustainable. At the present pace, information technologies will soon be responsible for more than 10% of global electricity consumption. Photonics – the technology that uses light to carry information – can come to the rescue, by providing low-energy, high-speed data transmission throughout the internet and within data centers. Additionally, photonics can enable novel applications of light in sensing and computing, with large potential impact on healthcare, agro-food and smart mobility. However, these promises can only be realized if increasingly complex photonic chips can be produced at a low cost. Eindhoven University of Technology (TU/e) performs fundamental and applied research aimed at making this dream come true. We talked to three key employees about their work in photonic integration: Professor Martijn Heck, Assistant Professor Ripalta (Patty) Stabile, and PhD candidate Marc Spiegelberg.  

What first attracted you to the field of integrated photonics?

Martijn: As a child, I was fascinated by lasers for obvious (sci-fi) reasons. During my studies in applied physics, I got a taste of their real-world application. This was during the internet boom in the 90s, which included optical fiber communications. Now, the main attraction for me is the balance between concrete real-world applications, such as enabling our current internet, and the potential for these cool and explorative applications in fields—like future all-optical and quantum computing.

Marc: I also like that balancing act between fundamental and applied research. I initially chose applied physics because it is broad and enables specialization at a later stage. During my studies, I learned about the importance of photonics and saw how fast the field is growing. 

And what attracted you to integrated photonics at TU/e? Why does TU/e stand out in this field? 

Patty: TU/e has been at the forefront of photonic integration technology worldwide for years and still is. 

Martijn: Right. I think what really makes TU/e special too is its location in Eindhoven, one of the global high-tech hotspots. Eindhoven has always had a strong tradition of linking industrial and academic research. So TU/e is positioned very well, literally and figuratively, to make our research relevant.

Working at such a renowned institution must afford you all some unique research opportunities. What research projects are you currently working on? 

Patty: I am working on brain-inspired optical computing. My short-term goal is to apply our state-of-the-art photonic integrated matrices to optical computing by designing a brain-inspired architecture, based on the integration of electronics and photonics. I want to surpass the operational speeds of processors at a much lower power consumption.

Marc: My work concentrates on the integration of photonic and electronic integrated circuits on wafer level, creating high speed, energy efficient modules for data and telecommunication. The classic approach is limited by inefficient electrical interconnects or costly packaging approaches, but my process eliminates these and offers improved co-design and scalability.     

Exciting work! What have been your biggest achievements on these projects in the past year?

Patty: My colleagues and I have recently demonstrated an optical neural network that, despite a limited number of neurons and layers, can already achieve extremely high data calculation rates. We have already reached eight billion operations per second!

Marc: My biggest research achievement of the last year was the successful demonstration of our 3D-integration of photonic and electronic circuits on wafer level. It was the result of a collaboration between Berenschot, Effect Photonics, Fraunhofer HHI, IBM Research, IMinds, Smart Photonics, TU/e IC group and TU/e PhI group within the European Project WIPE.

And what TU/e resources were essential in helping you reach these milestones?

Marc: The vision and trust of my supervisor was key to achieving my research goals. He believed my judgment that our cleanroom was missing a key tool. He invested in a new wafer alignment and bonding tool which enabled my work. 

Patty: For me, I would be remiss not to say a few words about the world-class NanoLab@TU/e cleanroom which plays a fundamental role in enabling our cutting-edge technology research. 

Marc: Agreed. And our cleanroom technicians are another important resource too. As I was a newbie in the cleanroom, I benefited from the advice and training of our cleanroom team who have collected several PhD generations of valuable knowledge.

Let's talk a little bit more about your experience as an employee at the university. What do you enjoy the most about working at TU/e?

Patty: Optimism, collaboration and dedication to society are central to working at TU/e. There is also special attention on social interaction and work flexibility that comes from unconditional and reciprocal trust.

Marc: It's true, the collaboration within the university is impressive. It permeates all the different groups and institutes.

So does that mean you would recommend TU/e to other academics looking for a research position?

Martijn: Of course I would recommend TU/e! There is a whole spectrum of opportunities available here to match your interests. It's perfect for young researchers whose interests will evolve. The university’s location in Eindhoven allows them to interact with industry and gives them opportunities to pursue a non-academic job after their PhD or postdoc if they wish.

Patty: It's a yes from me too. TU/e has been at the forefront of photonic chips worldwide for years and still is. TU/e publications have high citation scores and the university’s cutting-edge research regularly wins prestigious grants. Our university has also been ranked number one by Times Higher Education Ranking for collaboration with industry and we have the highest number of part-time professors from industry in the Netherlands. You can find plenty of opportunities here.