Laser 2019

•••2••• Innovationen Markus Lindemann is working on the development of ultrafast spin lasers as part of his doctoral thesis. Photo: RUB, Kramer Spin lasers facilitate rapid data transfer Technology may reduce energy consumption for transmission of information in bre optics E ngineers at Ruhr-Universität Bochum have developed a novel concept for rap- id data transfer via optical fibre cables. In current systems, a laser transmits light sig- nals through the cables and information is coded in the modulation of light intensity. The new system, a semiconductor spin la- ser, is based on a modulation of light polari- sation instead. Spin lasers work at least five times as fast as traditional systems, while consuming only a fraction of energy. Unlike other spin-based semiconductor systems, the technology works at room temperature and without any external magnetic fields. The researchers used the lasers to gener- ate a light wave whose oscillation direction changes periodically. The result is circularly polarised light that is formed when two lin- ear perpendicularly polarised light waves overlap. In linear polarisation, the vector describing the light wave’s electric field oscillates in a fixed plane. In circular polari- sation, the vector rotates around the direc- tion of propagation. The trick: when two linearly polarised light waves have different frequencies, the process results in oscillat- ing circular polarisation where the oscilla- tion direction reverses periodically at a us- er-defined frequency (over 200 gigahertz). The oscillation alone does not transport any information; for this purpose, the polar- isation has to be modulated by eliminating individual peaks. The researchers have veri- fied that this can be done in principle. They used numerical simulations to demonstrate that it is theoretically possible to modulate the polarisation and, consequently, the da- ta transfer at a frequency of more than 200 gigahertz. Two factors are decisive in order to generate a modulated circular polarisa- tion degree: the laser has to be operated in a way that it emits two perpendicular lin- early polarised light waves simultaneously. Moreover, the frequencies of the two emit- ted light waves have to differ enough to fa- cilitate high-speed oscillation. Spin lasers whose oscillation frequen- cy can be mechanically controlled: Electrical contact can be made via an adjustable needle. Photo: RUB, Kramer One laser in one machine Multi-functional tools for sheet metal processing Four partners are developing multi-functional laser tools to master the changing production and technical challenges of new, electric vehicle designs. Fraun- hofer ILT is coordinating the pro- ject and will appeal in particular to small- and medium-sized com- panies. Fast-changing products, fluctu- ating batch sizes and innovative production concepts: Hybrid lightweight construction and electromobility require a balanc- ing act between flexibility and productivity. “In volatile mar- kets, laser technology combined with digitalization is a predes- tined enabler for cost-effective production,” explains Dr. Dirk Petring, group leader at Fraun- hofer ILT and coordinator of the joint project “Multifunctional ro- bot technology with a universal laser tool for separating, joining and additive manufacturing pro- cesses in semi-bionic lightweight e-mobility – MultiPROmobil”. Fraunhofer ILT is developing a multi-functional laser process- ing head and robot technology for the flexible and economical production of sheet metal com- ponent assemblies. In the future, this head will not only enable users to integrate cutting and welding but also to additively generate structures. The latter process already works with a replaceable nozzle module. The project partners are currently working on optimizing the com- bi-head in such a way that it can execute all three processes in a production plant “on the fly” – i.e. without changing the optics or nozzles. The project is also focused on de- veloping intelligent design and simulation software for an opti- mized process chain. The project partners predict that engineer- ing efficiency can be increased and startup times reduced by around 30 per cent each. In ad- dition, they want to reduce unit costs and resource consumption by at least 20 per cent each. Processing of an automotive structural component with the multi-functional laser tool Photo: Fraunhofer / Thomas Ernsting Continued from page 1 The Multi-Power Family F +49 (0) 30 530249-10 | info@protech-berlin.com MEET AND TALK AT LASER MUNICH PROTECH OPTIC PRODUCTS GMBH www.protech-berlin.com