Lateral Current Injection Membrane DFB Lasers

• Applicants: Dr. Markus Kantner; Professor Dr. Martin Schell
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567090370

The project "Lateral Current Injection Membrane DFB Lasers" (DFB: distributed feedback) aims at the research and development of novel laser diodes that promise new records in terms of high modulation bandwidth and low laser threshold current due to their unique design. This is enabled by a novel membrane structure that allows for a significant miniaturization without losing the optical waveguiding capabilities. In a collaboration between the Technical University of Berlin (TUB) and the Weierstrass Institute for Applied Analysis and Stochastics (WIAS), the potential of these devices is to be researched both theoretically and experimentally in a multi-stage process and ultimately exploited to the maximum. Since existing simulation tools for semiconductor lasers are primarily designed for classical vertical current injection, a new simulation model tailored to the special features of LCI membrane lasers (LCI: lateral current injection) is required to fully capture the complex interplay of thermal, electronic and optical effects in the laser. The multi-physics simulation model and software, wich will be developed at WIAS in the course of the project, will enable the investigation of the interplay of numerous design parameters as well as the optimization of the device design in view of various figures of merit using mathematical optimization techniques. At the same time, the TUB will establish the technological basis for manufacturing of LCI membrane lasers based on indium phosphide semiconductors. By means of the experimental characterization and analysis of different manufactured design variants, e.g. for threshold current, output power and modulation behavior, the simulation model developed at WIAS will be calibrated and verified using measurement data. Extensive numerical simulations and model-based optimization studies will subsequently guide important design decisions for consecutive iterations of component manufacturing. At the end of the project, there will be, on the one hand, a comprehensive simulation tool that can provide optimized design parameter sets to meet desired characteristics of a LCI membrane laser. On the other hand, there will be LCI membrane DFB lasers with a threshold current of well below 1 mA and a modulation frequency bandwidth above 40 GHz (without utilizing photon-photon resonance). A design variant realized for the first time at TUB, in which the membrane lasers (in contrast to all previous publications) remain on their initial substrate during the entire manufacturing process, provides the starting point for the monolithic integration with other optical semiconductor components.

• DFG Programme: Research Grants
• Co-Investigators: Privatdozent Dr. Martin Eigel; Dr. Martin Möhrle