Photonics in Practice: From Research to the Forefront

Interview with Dr. Hanjo Rhee, CTO and Dr. Christoph Theiss, COO of Sicoya GmbH

Sicoya GmbH Photonic Wafer
A complete photonic wafer under the microscope, ready for inspection of photonic integrated circuits

Silicon photonics is regarded as a key technology for the next generation of optical data transmission. Sicoya GmbH, based in Berlin, is among the European pioneers in this field. The company develops photonic integrated circuits that enable the highest data rates in the smallest of spaces, and this with high energy efficiency, technical complexity and industrial scalability. In conversation with CTO Dr. Hanjo Rhee and COO Dr. Christoph Theiss, it becomes clear how strongly Sicoya focuses on technological excellence, but also on dialogue with the market – and what impressive development it has undergone since its founding in 2015 from a university spin-off to an internationally sought-after technology supplier.

Dr. Hanjo Rhee, CTO of Sicoya GmbH
Dr. Hanjo Rhee, CTO of Sicoya GmbH
Dr. Christoph Theiss, COO of Sicoya GmbH
Dr. Christoph Theiss, COO of Sicoya GmbH

Wirtschaftsforum: Dr. Theiss, Dr. Rhee, how did Sicoya come into existence?

Dr. Christoph Theiss: Sicoya was founded in 2015 as a spin-off from TU Berlin. Four of the five founding members, including Dr. Rhee and myself, had conducted intensive research in the area of silicon photonics there. Together with an industry expert, we wanted to convert our scientific results into marketable products. The subject was technically challenging, but we had a clear vision.

Dr. Hanjo Rhee: Developing our technology was demanding. We work on a complex BiCMOS platform, where a design cycle often takes three-quarters to a full year. The initial period was marked by intense research and product development. Accordingly, we needed investors who believed in long-term success. The first market entry with finished transceivers took place in 2019/2020, a crucial step into the commercial market.

Wirtschaftsforum: Since 2021, Sicoya has been part of a Chinese conglomerate. What has changed as a result?

Dr. Christoph Theiss: We are a subsidiary but continue to operate independently. In Berlin, the focus is on development and chip design. The modules and markets of the parent company in China are clearly separated from ours. This structure provides stability, but also flexibility, to focus on our strengths.

Dr. Hanjo Rhee: Our technology was pioneering from the start. We were among the first in Europe to bring silicon photonics to market readiness. Our designs were highly integrated early on, an advantage we maintain to this day. The combination of photonic and electronic functions on a single chip is complex, but offers significant efficiency gains.

Sicoya GmbH Fine Structures
Fine structures and lines demonstrate the high integration density of the silicon photonics technology in the close-up of a photonic wafer with 300 mm diameter

Wirtschaftsforum: What does the strategic alignment look like today?

Dr. Christoph Theiss: At the beginning of 2024, we decided to withdraw from module production. Manufacturing was capital-intensive and no longer scalable efficiently. Instead, we are now focusing on our core business: the development and delivery of photonic and electronic chips. For this, we are cooperating with a high-performance European foundry. Our customers then integrate the chips into their modules themselves. We do what we do best: innovation at the interface of photonics and electronics.

Dr. Hanjo Rhee: Key is the close exchange with large end customers like hyperscalers and cloud providers. Our chips are developed along their roadmaps: the technical requirements ultimately define the architecture and performance. This proximity to the application not only ensures our relevance but also our capability for innovation.

Wirtschaftsforum: How is the market environment structured?

Dr. Christoph Theiss: There are only a handful of major data center operators who are also driving innovation. They dominate the demand. We are in direct or indirect contact with them. Even though our immediate customers are often module manufacturers, specifications usually come from the end customer.

Wirtschaftsforum: Have there been personnel changes due to the strategy shift, and how have your tasks within the company evolved?

Dr. Christoph Theiss: In the course of the realignment, we have streamlined, from around 80 employees in 2023 to currently almost 40, supported by external specialists. The focus is now clearly on research, product development, and technical excellence. This focus not only creates efficiency but also more clarity. I took on commercial and strategic responsibility early on - initially as responsible for processes and production, today as COO. What motivates me especially is making a complex technology commercially viable and positioning the company for long-term success.

Dr. Hanjo Rhee: I was already involved with silicon photonics during my doctorate at TU Berlin. Since the founding, I have been responsible for the design of photonic integrated circuits. Today, as CTO, I lead the technical orientation and innovation strategy. It is fascinating to see how concepts from research can be translated into market-ready products.

Wirtschaftsforum: What are the key success factors of Sicoya?

Dr. Hanjo Rhee: Our ability to integrate electronic and photonic functions on a single chip gives us a clear technological advantage. Our chips are compact, powerful, and tailored to the specific requirements of the end customers. We provide not just standard components but real differentiation.

Dr. Christoph Theiss: Added to this is a deep understanding of the market. Our technical marketing is directly linked to development – customer feedback is incorporated into product design at an early stage. This is the only way we can develop solutions that are technologically relevant, today and in the future. Innovation arises in dialogue with the market.

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