When developing novel laser systems, research needs to analyze optical parameters, such as the average power, the absorption of the pump power, the optical spectrum, the pulse shape and the repetition frequency in order to characterize and optimize laser systems. In high-power lasers, mode instability occurs from a certain power value. This means that the laser no longer emits the basic transverse mode, but shows a temporal dynamics in the intensity distribution. This behavior prevents further power scaling and results in poor beam quality of the laser. To suppress the effects that are undesirable for applications, the institutes Fraunhofer IOF and Fraunhofer ILT fundamentally analyze the laser systems for modulating instabilities (e.g. beam quality). On the basis of the detailed analysis, they then develop novel fiber, pump and laser designs to suppress the mode instabilities and, thus, to scale the power of high-performance fiber laser systems even further.
For the simulation of laser systems and the generation of radiation fields, various tools for simulation are available at the institutes, covering the following areas:
- Wave optics
- Geometrical optics
- Hydromechanics, structural mechanics
- Data evaluation (statistics, classification, etc.)
To analyze wave fields further and optimize beam sources, the institutes have a number of numerical models and tools with which the complex conditions can be described and modeled in a variety of beam source constellations. In addition, they develop in-house tools that enable laser developers and beam source manufacturers to optimize their own systems, such as the optical lens simulation OPT developed at the Fraunhofer ILT and a design software for free-form optics.