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?
Akanksha Kapoor has always had a fascination for lighting and light emitting diodes (LED) applications. The fact that in everyday life we are surrounded by the technologies that underlie these applications, motivated her to pursue the topic further. She obtained her PhD in flexible LEDs at the CEA Institute in Grenoble, France. In her research, she explored nitride materials for long wavelength visible LEDs. The added functionality of flexibility make these devices attractive for a variety of applications, such as wearable gadgets and biomedical applications. For the next step in her career, she was looking for a similar mixture of academia and industry. It turned out, a Postdoc position in the Photonic Integration (PhI) research group at TU/e offered exactly this: plenty of research and academic work, all in close collaboration with equipment manufacturer AIXTRON. In the beginning of 2021, Akanksha joined the TU/e, where she now works as an Epitaxy Researcher.
Akanksha Kapoor, Epitaxy Researcher at TU/e. Photography by Bart van Overbeeke.
As a Postdoc at TU/e, you were heavily involved in the OIP4NWE project. Can you explain what the goal of this project was?
“The goal of OIP4NWE was to develop a brand new pilot line that enables the transition from 3 inch to 4 inch indium phosphide (InP) wafers for photonic chip production. When you are scaling up, you need compatible tools. One of the prime objectives was therefore to bring in new infrastructure. The beautiful output of the project consists of two tools we now have in the NanoLab: a next-generation epitaxy tool provided by AIXTRON (G10 model) and the SPTS cluster tool. The MOCVD (Metal Organic Chemical Vapour Deposition) reactor is used to grow the layers of indium phosphide that our chips consist of. Besides being able to handle significantly larger wafers, the tool has automated wafer handling, eliminating the need for manual interference. This is an advanced feature which you do not normally see in equipment used at universities. The cluster tool is a cassette-based tool, enabling high throughput. It is suitable for higher volumes of PICs, which is what we are working towards.”
Your current role is Epitaxy Researcher. What does your day-to-day job entail?
“The word epitaxy comes from the Greek roots ‘epi’ and ‘taxis’. It means ‘to grow in an ordered manner’. Every material has a crystal structure; you have to grow one crystal over the other in an ordered way. A good photonic chip literally starts with good material quality. In my day-to-day job, we try to grow different materials based on indium phosphide and exploit the different growth conditions. The goal is to achieve the optimal properties: more uniform layers which contain minimum defects and are more uniformly doped. This will, for example, lead to more controlled and better emission efficiencies of the lasers we make on chip. So I spend my time mainly in the cleanroom focusing on the wafer growth and their metrology.”
Can you explain the project you are working on in simple terms? Why is it important?
“Addressing the limitations of the current platform is extremely important. We are now working to improve some of the existing building blocks in epitaxy. For example, one of the ambitions is to produce 1550nm lasers for higher temperature operations. The PhI group has wanted to do this for a long time and since we now have a high end tool that can produce high quality materials, we can finally integrate some new alloys in the existing PIC platform and fabricate fully working chips. We are also looking into low loss waveguides by exploring the doping limits of the tool.”
What do you find challenging in your current job?
“Well, it was intense during the tool release. I remember in the beginning with AIXTRON, we were in the cleanroom for 5-6 hours at a stretch doing marathons of epi runs for a thorough understanding. The tool is now fully operational. But since it is high-end equipment, I encounter a mix of scientific and technical challenges. Downtime, updates or maintenance on the tools can cause delays. However, the people at AIXTRON are very supportive and approachable. The epitaxy tool officially still belongs to them, so it is as much their baby as it is ours. They are eager to support it and learn about the indium phosphide platform. On the scientific front, there are some hardware developments in progress to improve the material quality and homogeneity. There are still some open questions to address: diffusion with dopants, the possibility for etching materials in-situ and the installation of some new material lines in the reactor.”
Akanksha Kapoor, Epitaxy Researcher at TU/e. Photography by Bart van Overbeeke.
How do you explain your job to people outside of this industry? How do you make it understandable and exciting?
“When I was still working on flexible LEDs, it was easy because I could physically show it. The work I’m doing now is more tricky to explain. I usually start by bringing someone’s attention to their mobile phone. Every year, brands like iPhone and Samsung release a new version of their phones. What changes is that every year, the phone contains a new chip that is more robust. These chips need to have certain properties, with a certain thickness and composition and a specific design. Growing these chips, that is what I’m focusing on.”
Is there somebody in the photonics industry that inspires you? And why?
“If I talk about science in a wider perspective, it is definitely Einstein. I have watched and read many movies and articles from him. He is such an interesting person. If I talk about integrated photonics, it would be Meint Smit. When I joined the PhI group, I learned that he is the person that laid the pillars for this group and this technology. And when I saw he received the John Tyndall award, I realized he is a truly a pioneer. It is always a pleasure to read his articles.”
How do you experience the European PIC ecosystem?
“It is open, dynamic and fast. Fast in the sense that a big part of the ecosystem is next door to us and developments happen rapidly. Every time I read a PhD thesis, I am amazed at what has been achieved. We have so many great minds in our group. I think for example about the PhD work of Arezou Meighan to make high band modulators and the recent work by Yi Wang. We have a great way of collaborating with people and companies that have different skills and expertise. Just by reading roadmaps, research outputs and publications, I can see we are getter closer to where we want to be every day.”
What are your plans for the coming years?
“I definitely see myself working in this industry for many years to come. Sometimes there is a new development in the technology aspect, sometimes a new fundamental research idea pops up. The learning and exploration is increasing day by day, and I look forward to address some of the open questions in the epitaxi community: a better control over dopants, bringing indium phosphide and silicon epitaxy closer together, to name a few. Although I am focusing on epitaxy now, I know there are different building blocks that I can explore. I would like to get more of an overview of the full process line. When I talk to peers, it is valuable to see that they have dedicated expertise, but having the full picture in your head completes the story. Especially with epitaxy, having a wider angle could really help me in the future.”
Do you have any tips for people starting out in the field of photonics, or things they should keep in mind?
“It is always good to start with a plan, but it could very well be that while you are digging deeper and becoming more familiar with the technology, you come across different platforms that catch your interest. It can be difficult to keep pace with this technology and it is okay to have flexibility and deviate from your plans. Photonics is here to explore and be fascinated by!”
Would you like to know more about OIP4NWE and Akanksha’s contributions to this project? Check out this article by the Eindhoven Hendrik Casimir Institute in their SPOT ON Integrated Photonics magazine.
Curious about what job opportunities the photonic integration community has to offer? Check out our career page.