1 - 4 of 4
-
PublicationCompensation of structure distortion in nonisothermalhot forming of laser structured thin glass( 2024-06-12)
-
PublicationPrecision Glass Molding of Fused Silica Optics( 2024-05-28)
-
PublicationEfficient Fiber-Photonic Integrated Circuit Connection via Wafer-Scale Glass Molding( 2022-12-12)Increasing demand for higher data rates in data centers is driving efforts to produce single-mode optics, which substantially improves the commonly used infrastructures. However, the fiber cou-pling to photonic integrated circuits (PICs) is currently a bottle neck. The optics needed to link optical fibers to PICs are sub-millimeter in size and call for extreme precision both at the manu-facturing as well as the assembling stage. Using glass instead of plastic optics increases the optical performance and therefore, the transmissible data rates but results in higher production costs. Fraunhofer IPT and partners developed an innovative, efficient glass fiber coupling technology based on the replicative process of glass molding. In a glass molding process, a glass preform is heated until the viscous state and afterwards pressed into the desired shape using two high-precise molds. This process permits the direct and efficient manufacture of high shape accuracy and sur-face quality optics without any mechanical post-processing steps. To fabricate the fiber couplers, two different glass molding technologies were explored and compared: The highly precise, but slow isothermal process of precision glass molding (PGM) and the more efficient, but less precise non-isothermal glass molding (NGM). A scale-up strategy has been developed which is based on a wafer-scale approach. This allowed producing a large number of identical elements in one mold-ing operation out of a single glass wafer, which increased the efficiency both of the manufacturing process and of the subsequent assembly operations. The development covers all aspects of the realization of single-mode fiber coupling - from the optical and electrical design of the connectors and PICs through process technology, machine tool manufacture and assembly technology to ap-plication within the system and the analysis of the coupling efficiency from fiber to PIC.
-
PublicationFlying Fuel Cells and the challenges for bipolar plate forming( 2022-06-14)The influence of increasing resource scarcity and climate change has a significant impact on aviation. Therefore, the European Commission has set ambitious goals with a 75% reduction in CO2 and a 90% reduction in NOx as part of the Flightpath 2050 vision. Achieving these goals requires the use of disruptive technologies in aviation, especially in propulsion. In addition to the use of Sustainable Aviation Fuel (SAF), the direct use of hydrogen is a promising alternative. There is the possibility of the direct use of liquid hydrogen in gas turbines as well as the use of fuel cells. In the last-mentioned application, the fuel cell acts as an energy converter and powers the primary electric drives, so that there is the potential to fly emission-free, especially for short- and medium-range flights. However, successful integration of the fuel cell into the aircraft's powertrain requires a significantly increased gravimetric power density compared to the status quo. Furthermore, the fuel cell and the entire manufacturing process chain must fulfill the very high safety requirements of aviation. Therefore, the bipolar plate and, respectively, its production process are key elements for the flying fuel cell. To fulfill the high safety requirements of aviation during the forming of the bipolar plate, various fields of action exist. Within the scope of the presentation, current possibilities of forming simulation will be shown in order to understand the cause-and-effect relationships and thus significantly improve the forming process and the resulting product quality for an optimal integration into a flying fuel cell. Furthermore, current digitalization approaches in the context of forming bipolar plates for flying fuel cells will be presented in order to manage the complexity from the dimensions of design requirement, manufacturing process chain as well as sustainable production.
