People behind the PICs | Wim Bogaerts

People behind the PICs | The Photonic Integrated Circuits (PIC) industry is booming. Companies in the field are growing steadily, start-ups with innovative solutions are popping up regularly, and the search for technical staff seems never-ending. In this interview series, we are curious to get to know the people behind the PICs. Who are the energy forces driving this technological revolution, and what motivates them? What can future photonics engineers expect from a career in this field?

Although he started working in the field of photonics “by accident”, Wim Bogaerts’ career in silicon photonics now spans almost three decades. After obtaining a master’s degree in Engineering (Applied Physics), he went on to pursue a PhD in the Photonics Research Group of Ghent University-imec. In 2010, he became Professor at this university, specializing in advanced design methodologies for integrated photonics and tackling the challenges that form the design gap for silicon photonics. After co-founding Luceda Photonics in 2014, with the aim of bringing the IPKISS software and other advanced design tools to the rapidly growing photonics market, he returned to his fundamental research interest. Since 2016, he is working full-time again as a Professor at Ghent University-imec, where he is closely involved with the silicon photonics Multi-Project Wafer (MPW) service known as ePIXfab.

Wim Bogaerts, Professor in Silicon Photonics at Ghent University. Photography by Ghent University.

Going back to the beginning: how did you get started in the field of photonics?

“In quite an accidental way. During my master, all of my major topics were in nuclear physics aside from a course in opto-electronics, as it was called in that day. And my master thesis actually had nothing to do with photonics. However, towards the end of my master I had quite a few options to do a PhD and one came about in a surprising way. I was doing a course taught by Roel Baets and he asked if there was someone who was good with PowerPoint. I ended up as his student assistant, basically making his slides look nice. After a while, he asked me if I wanted to do a PhD in photonic crystals. These are, simply said, periodic structures of material that scatter light in a peculiar way. At the end of the 90’s, photonic crystals were the next big thing; they were going to solve the world’s major problems. Today we know better that the engineering of photonic crystals is very hard and they are sensitive to variations. It seemed promising but it has not materialized. But, although the conclusion of my PhD was not that these crystals are amazing, it did introduce me to the technologies that we use today to make Photonic Integrated Circuits (PICs). That’s how I rolled into the silicon photonics field. And from there, one thing led to the next. And the next.”

One of the things it led to is the foundation of Luceda Photonics. How would you describe the process of founding this company?

“Luceda was founded in 2014, but we were already working on its foundations in the early 2000s. After diving into the waters of silicon photonics, it quickly became clear that there were no design tools for making PICs. At least not at the scale that was needed. So I started writing my own Python code for me and my colleagues to use. After a while, people outside of Ghent University and imec started using it as well, which presented us with a choice: either we go open source or we make it commercial. We looked into what was viable and sustainable and how we could, at the end of the day, pay our bills. Pretty soon we realized that the only way to make it work at that time was a commercial approach. That’s when the ball started rolling and the process really kicked off. I liked it a lot. Founding a company and then going with it in the early years is very different from academic research. The only thing that matters is creating value for the customer. If an entire team is focused on that single common goal, it creates enormous momentum and an almost peculiar type of focus. It makes you move very rapidly with an energy that you typically don’t see in academia. Especially with a small team. It becomes an ‘us against the world’ kind of thing.”

After two years in industry, you went back to being a full-time Professor. What prompted this decision and how did you experience the transition?

“It was always the plan that after two or three years, once Luceda was up and running, I would go back to academia. When we started with the company, there was a lot of knowledge in my head that needed to be transferred to the team. I also had an extensive network of contacts in the field, which was valuable for the company and made my involvement in its early days very important. Although I loved the whole process, I am also a person that always has a lot of new ideas and that is maybe a better fit for academia. Besides, I received an ERC grant, which is a big sum of money to do exploratory research. It essentially forces you to go back to academia, as in a start-up the work you do is very much in the here and now. I do sometimes miss the energy and team spirit of a start-up, but I am still in close contact with the people from Luceda and give advice where I can.”

As a Professor, how do you prioritize between teaching activities, research, conferences, et cetera?

“That’s the million dollar question! I struggle with that every day. I very much enjoy each of these things on their own but when you put them all together, it’s a lot. I like going to conferences because it is where you get to interact with all kinds of people and generate ideas. Luckily, my teaching load is not too heavy, it’s manageable. And I don’t get around to doing hands-on research anymore but I coach PhD students and have a lot of stimulating discussions with them. The funny thing is, as a Professor you get selected and promoted for being a good researcher and teacher but in the end, you need to be a good team leader and manager. There is a lot of effort that goes into that. Ten years ago, I was still doing hands-on research myself. Now my work is about putting ideas in other people’s heads and letting them deal with it on their own. Even after all these years, I still find that challenging.”

What is your role in ePIXfab and how would you describe ePIXfab’s role in the integrated photonics community?

“Today, I am the chair of ePIXfab. I have taken over the position from Roel Baets in September 2023. ePIXfab is an alliance of many European actors in academia and industry, and its ambition is to foster the European silicon photonics community as part of the global photonics and the global silicon technology ecosystem. We are right in the intersection of these two ecosystems. And today, the field of photonic integration is changing very rapidly, which creates very interesting opportunities for ePIXfab and its members. Moreover, what I think ePIXfab does really well and what makes me enthusiastic, is that we organize several workshops and summer schools throughout the year. You see new people entering the field with a lot of drive. In general, the field of PICs is growing at a tremendous pace. Being there in the center of that and seeing how the things we put together ten to fifteen years ago are now really gaining momentum, is really exciting to me.”

What is something you are working on right now that really excites you?

“The main topic that I have been working on since I came back to academia after Luceda, is programmable photonics. It is when you create a photonic chip that you can program to do different things. I truly believe we need this capability to make photonic chips a success. We need to make it easy for product developers to rapidly integrate multiple functionalities on a single chip. Now it can easily take a year between iterations; you need to design, fabricate and test. If you can buy a chip and just program it, it can greatly accelerate your experimental pace. In electronics this already exists but in photonics we’re not there yet. Most of the PhD students I coach are working on this. We’ve had interesting results lately that show that we can get such chips to work. Interacting with my students and seeing that this is moving forward really excites me.”

In which application areas do you think PICs have the most potential?

“What we now know is that for the foreseeable future, the data center market will be pushing the technology development in our field. However, this market is probably never going to be large enough to sustain the entire ecosystem. We need applications beyond fiber optic communication. If electronics would have stayed in calculators, it would never have become as big as it is today. And you see electronics everywhere now; the scale of the volumes is what keeps the technology innovating. Photonics is orders of magnitude away from such volumes. We need photonic chips in way more applications. And we need to make it easier for people entering the field to come up with new ideas. Creating that volume will take time, of course. If there will be one killer application, I don’t know it yet, but I hope there will be more than one, because we need diversity. Most likely many applications will involve sensors, as we live in a society where we want to collect more and more data. Continuous health monitoring could revolutionize medicine, for example. Photonics is very likely to play a role in that.”

How do you look at developments in hybrid integration, i.e. combining different production platforms on a single chip?

“It is an obvious evolution. In photonics, you need different materials to get the most out of your chip. Hybrid or heterogeneous integration, where you mix materials to get the best of both worlds, is the obvious way to go. For the foreseeable future, it’s going to be the way things are done. In silicon electronics, they have done a similar thing. Silicon electronic chips now contain many more materials then they used to. Every time there was a bottleneck, they eliminated the obstacles that were in the way to bring the necessary new materials into the fab. I do think silicon will continue to dominate as the wafer substrate of choice, because sticking to silicon means you can keep using the fabrication tools and methodologies that have been developed for electronics. This differentiates silicon from indium phosphide. However, in the future I see a lot more collaboration happening between silicon fabs and indium phosphide fabs. The indium phosphide will probably be processed in a separate fab, either for a stand-alone chip or to be integrated onto silicon afterward.”

How do you explain your job to people outside of this industry? How do you make it understandable and exciting?

“I usually start by saying that I make computer chips that work using light instead of electrical signals. If they ask where those chips are used, I tell them you can send a lot of information through optical fibers, but at the end of these fibers you always need a chip to convert this information. To basically plug it into your computer. Most people can grasp that optical fibers are used for communication, as every once in a while a guy comes to their house to install an optical fiber so they can watch television, for instance. It is easily explained that at the end of the fiber, there needs to be a chip. That is usually sufficient to satisfy their curiosity, but it we take it further, I explain that you can use light for many other things, and that we can expect such chips to be used in health sensors for smartwatches.”

Is there somebody in the PIC industry that inspires you? And why?

“There are plenty, where to start. I have always looked up to Roel Baets as he was my PhD supervisor and I find him a very inspiring person. A lot of the ways I do things is inspired by him. But there are so many great people in the PIC ecosystem. I can think of people both older and younger than me that I find inspiring. I think a lot about the networks that were created with earlier projects, like ePIXnet, which eventually became ePIXfab and JePPIX. To me, those projects and the people that coordinated them, really show the value of collaboration. It propels your ecosystem and your research forward. They were the first projects of their kind and I still consider them extremely enlightening. Over the course of five years they completely changed how collaboration in the field of photonics worked. That’s a legacy that is still there today; the field in Europe has become much more collaborative.”

What has been challenging in your career and what was the most rewarding?

“There are quite a number of things that I have been, and still am, really proud of. Having founded Luceda is definitely one of the most rewarding things, but there are many things along the way that led to the creation of Luceda that I am equally proud of. The most challenging part of my career is definitely balancing everything. As you grow in your career as a professor, the number of responsibilities grows along. Juggling all of them remains a challenge. I wouldn’t say I have a lot of free time outside of photonics. When I do, I mostly like reading or watching a good series. I also like history a lot, so that is usually the subject of the podcasts I listen to when I am cycling to work in the morning.”

Do you have any tips for people starting out in the field of photonics, or things they should keep in mind?

“Be open about your own capabilities and shortcomings and try to collaborate with people as much as you can. There is a big chance that other people know more about specific topics than you do, so tap into the brains of your colleagues. The PIC industry is still in a very early phase. We are using industrial tools and a lot of companies are involved, but in terms of processes and markets we are still so immature. By collaborating, we can make the whole ecosystem grow much faster.”

Curious to know which job opportunities the photonic integration community has to offer?
Check out our career page.