We are seeking a Senior Principal Optical Systems Engineer to lead the architecture, design, modeling, integration, characterization, and validation of advanced optical microsystems and photonic test solutions. This senior individual-contributor role owns complex development efforts from concept through production release and applies deep expertise in optics and photonics to resolve multidisciplinary technical challenges. This is an on-site position based in Karlsruhe, Germany, where Keystone does exciting work on advanced 3D-printed micro-optics and optical probe heads. The role is part of our parent company, FormFactor, and will work in close collaboration with a team on the U.S. West Coast. Candidates should be willing to travel to the U.S. several times per year. FormFactor, Inc. (NASDAQ: FORM), is a leading provider of essential test and measurement technologies along the full semiconductor product life cycle — from characterization, modeling, reliability, and design debug, to qualification and production test. Semiconductor companies rely upon FormFactor’s products and services to accelerate profitability by optimizing device performance and advancing yield knowledge. The company serves customers through its network of facilities in Asia, Europe, and North America. Tasks The successful candidate will provide technical leadership across engineering, manufacturing, quality, software, and commercial teams; translate customer and product needs into system requirements; and establish robust design, simulation, test, and validation methods. This role influences technical roadmaps and engineering practices through expertise and collaboration rather than direct people management. Optical System Architecture and Product Development • Lead development of advanced optical systems, micro-optical components, and photonic test solutions from concept through commercial deployment. • Translate customer, product, and application requirements into system architectures, performa