Karl Merkel, Business Development / Application Engineer, Keysight Technologies
Karl Merkel has worked in test and measurement for over 30 years. In 1984 he joined Hewlett-Packard as a staff engineer in Palo Alto, California. In 1987 he moved to Colorado Springs, Colorado where he continues to work as a business development / application engineer for Keysight’s photonic test equipment. Karl has worked with a wide range of Keysight optical test products in R&D, manufacturing and installation / maintenance applications.
An Approach for Wafer-Level Optical Polarization Resolved Spectral Measurements
With the widespread move to wafer-scale production using integrated photonics technology, the throughput for testing needs to be optimized. A significant part of the time for optical testing on wafers and chips is often used for optimizing the probe coupling. An extra aspect of this for optical coupling involves testing with the intended polarization alignment of the light. Planar devices often have differing optical properties for light polarized parallel (TE) or perpendicular (TM) to the device plane. The coupling from the probe can also have a strong polarization dependence, especially with surface grating couplers. Often during initial research and development, this is dealt with by manually aligning the polarization as part of the probe adjustment process. But that quickly becomes a bottleneck for getting fast automated and reproducible results. Especially for spectral measurements of wavelength dependence, the attempt to hold this polarization alignment while the wavelength is scanned is a real challenge for both speed and reproducibility. A powerful way to address this challenge is with fast automated measurements of the complete polarization dependence, from which the results for aligned polarization can be extracted. Results using a swept wavelength tunable laser based approach will be presented.