Computer chips are getting smaller and faster every year, but one challenge remains unsolved: combining electronics and photonics on a single chip. Although components such as micro LEDs are available as individual chips and waveguides as tiny fiber optic cables, the materials required are too different for a harmonious chip. A new type of etching process could now provide the decisive breakthrough for combining light sources and light guides.
Computer chips are getting smaller and faster every year, but a specific challenge remains unsolved: how to combine electronics and photonics on a single chip. Although components such as micro LEDs are available as individual chips and waveguides as tiny fiber optic cables, the required materials are too different for a harmonized chip. A new type of etching process could now bring the decisive breakthrough for combining light sources and optical fibers.
It will be particularly worthwhile for the German photonics industry to keep a close eye on Braunschweig and Jena over the next few years: In the OptoGaN project, researchers from the Technical University of Braunschweig and the Friedrich Schiller University Jena are working on porous gallium nitride.the joint idea of the research groups involved offers a wide range of potential applications. The project partners want to realize three of these ideas as demonstrators together with one start-up each. These will then benefit technologies such as waveguides, neuromorphic computers and the Quantum Valley Lower Saxony ion trap quantum computer. At the same time, the newly founded Nitride Technology Center (NTC) at the TU Braunschweig supports the further development of nitride technology at the highest level and its application. The field of application of these technologies could look like this: Large laser systems are currently still needed to manipulate the ions of the quantum computer, for example. If more and more quantum bits are to be calculated together in the computer, this laser system must become significantly smaller - at best to chip size. However, silicon dioxide for waveguides on chips absorbs precisely the critical wavelengths of light. Here, porous gallium nitride could offer an alternative and bring the customized light to the individual ion with minimal loss.
Complementary expertise in dealing with gallium nitride
The porous semiconductor is based on a new selective etching process. The researchers use it to create elongated, air-filled channels - pores - in the gallium nitride structures. This even makes three-dimensional waveguides with complex optical light guidance conceivable. As gallium nitride and the process are compatible with existing LED production methods, integrated electronic and photonic circuits will also be possible. In order to realize the innovative semiconductor channels for light conduction, the researchers from Braunschweig and Jena are bringing together complementary expertise and special equipment. This is because the etching process used here has both an electronic and a chemical component. First, the Braunschweig researchers produce the base material layer by layer. The semiconductor chip then travels to Jena for ion implantation. The researchers from Jena dope the chip and change its electronic properties in a targeted manner. Finally, the chip has to return to Braunschweig, where the chemical etching process forms the final, porous structure.
About the project
The project 'Highly integrated microphotonic modules in nitride technologies', OptoGaN for short, is being funded by the Federal Ministry of Education and Research with around €600,000. The TU Braunschweig's share of the funding is € 450,000. The partners from Technische Universität Braunschweig and Friedrich Schiller University Jena started OptoGaN in 2023 for three years until October 2026.
www.tu-braunschweig.de/iht/forschung/gan-technologie
www.uni-jena.de/
