PhotoGeNIC — Photonics on Germanium – New Industrial Consortium
Popular-science summary
VCSELs are miniature semiconductor lasers that emit light perpendicular to the surface of the wafer. They are currently produced in very large volumes and are used, among others, in facial recognition systems, 3D cameras, data transmission, and LiDAR systems for autonomous vehicles. Such lasers are typically fabricated on gallium arsenide (GaAs) substrates. The PhotoGeNIC project investigates the possibility of replacing this material with germanium (Ge), which may enable the use of larger wafers, improve structural uniformity, increase production yield, improve heat dissipation, and reduce both the cost and environmental impact of the technology.
Within the project, technologies for the epitaxial growth and fabrication of VCSELs on germanium substrates are being developed, and their properties are compared with those of conventional lasers fabricated on GaAs. The resulting devices are to be validated in two practical demonstrators: an automotive LiDAR system and an industrial 3D camera. The project also develops new VCSEL concepts, including lasers based on Fano resonances and lasers with ultrafast control of the emitted beam direction.
Project objective
The main objective of the PhotoGeNIC project is to develop a technology for high-quality VCSELs fabricated on large-area germanium substrates and to demonstrate that they can achieve performance at least comparable to conventional VCSELs fabricated on GaAs substrates. The project includes the development of epitaxial growth technologies using MOCVD and MBE, the development of device fabrication processes, device characterization, and integration into LiDAR and 3D camera demonstrators. An important objective is also to establish a pathway toward the integration of VCSEL technology with silicon platforms, CMOS technology, and photonic integrated circuits.
Project partners
The PhotoGeNIC consortium consists of: Technikon Forschungs- und Planungsgesellschaft mbH, Austria – project coordinator, VIGO System S.A., Poland, Łukasiewicz Research Network – Institute of Microelectronics and Photonics, Poland, Lodz University of Technology, Poland, pmdindustrial GmbH, Germany, Centre National de la Recherche Scientifique – CNRS/LAAS, France, Umicore N.V., Belgium, XenomatiX, Belgium.
Role of Lodz University of Technology in the project
Lodz University of Technology is primarily responsible for the modelling, design, and characterization of new VCSEL architectures. TUL leads WP4, “New VCSEL functionalities and designs”, which is devoted to the development of new laser functionalities, in particular beam steering and the use of Fano resonances.
The TUL team designs epitaxial structures, oxide-aperture geometries, and coupled-cavity VCSEL configurations. It also develops the parameters of subwavelength gratings for VCSELs based on Fano resonances. TUL performs simulations and characterization of lasing properties, spectral characteristics, and far-field emission. Within the project, TUL leads, among others, tasks related to a Fano-resonance VCSEL and a VCSEL with beam steering controlled by independent current injection.
Lodz University of Technology is also responsible for the characterization of the static electro-optical properties of VCSELs fabricated on Ge substrates and for comparing them with corresponding lasers fabricated on GaAs substrates.
Expected impact of the project
The project may contribute to the development of a new generation of semiconductor lasers intended primarily for LiDAR systems, 3D cameras, optical sensors, and integrated photonic systems. From the end-user perspective, these technologies are important for the development of safer transportation and autonomous vehicles, spatial detection and imaging systems, and miniature electronic devices using distance measurement and environmental sensing.
The use of germanium may enable an increase in wafer diameter, improve structural uniformity and production yield, and reduce manufacturing costs. The project also foresees environmental benefits resulting from reduced use of GaAs substrates, the recyclability of germanium, and reduced production waste. Another important advantage of Ge is its favorable thermal properties, which are particularly relevant for densely packed high-power laser arrays.
An important scientific outcome of the project will be an improved understanding of new VCSEL resonator architectures, including those based on Fano resonances and coupled cavities, as well as the possibility of ultrafast control of the emission direction without the need for external mechanical components. The project may also open a path toward the integration of III–V lasers with silicon technology, CMOS, and photonic integrated circuits.
From an economic perspective, the project results are expected to support the development of the European photonics industry by providing technologies that may be scalable to mass production and applicable in the rapidly growing automotive, LiDAR, and 3D sensing markets.
Project funding
The project is implemented under the Horizon Europe programme, call HORIZON-CL4-2021-DIGITAL-EMERGING-01-07 – Advanced Photonic Integrated Circuits, as a Research and Innovation Action (RIA).
According to the budget presented in the proposal:
total eligible project costs: EUR 4 788 752,
budget allocated to Lodz University of Technology: EUR 806 800.