Ultra-efficient silicon photonic fiber-chip interface

Silicon Photonics (SiPho) is a fast-growing technology addressing many applications such as data and quantum communication but also sensing and imaging (LiDAR). Especially for communication applications, silicon photonics is playing a key role to have lower power consumption and higher speed at the same time with lower cost than traditional compound semiconductor photonics. As an importance of silicon photonics optical I/O increases, industry major players such as intel, Nvidia, TSMC, Samsung are also shipping the silicon photonics products or trying to have faster and energy-efficient products. As a world-renowned research center in this field, imec has in-house 200mm and 300mm CMOS pilot lines to process cutting-edge optical devices at wafer scale, including high-performance devices for light modulation, switching, coupling, filtering, and detection at data rates of 50GB/s and beyond.

This PhD research focus on developing high-performance fiber-chip interface to address the industry needs for next-generation products where more then ever every loss needs to be eliminated. Current fiber grating couplers are limited by its high loss, limited bandwidth, and polarization sensitivity. For high-channel-count or course wavelength-division-multiplexing optical circuits, it is crucial to increase the fiber interface optical bandwidth to facilitate wafer-level testing. For photonic receivers, a polarization-splitting fiber interface would reduce the difficulty for packaging. For many emerging applications including quantum photonics, it would also be desirable to have extremely loss low fiber couplers. To achieve these novel design concepts, it would be crucial to adopt advanced algorithms including machine learning. The PhD student is expected to carry out independent and novel research in the silicon photonics device platform team, during which he/she will master Python programming for scientific data processing, and the modelling, simulation, and characterization of silicon photonics devices and circuits.

In this research, the PhD student will carry out:

• Literature review of existing out-of-plane solutions for fiber interfaces
• Design, simulate, layout and characterize silicon photonics devices for efficient and polarization-diverse fiber coupling
• Improve the device performances compared to the state of the art by advanced optimization methods, such as classical local/global optimization methods and machine-learning-driven optimization.
• Improve the device design flow by algorithm-enhanced automation and parallel-computing-enabled performance evaluation
• Explore novel process and design concepts to enable relaxed alignment tolerance, lower polarization-dependent loss, and better manufacturing robustness. For example, lithography enhancement techniques and improved layer stack.