How to Make Optical Designs Right the First Time

Optical Solutions Editorial Team

May 13, 2024 / 4 min read

Before manufacturing an optical system, it is crucial to understand and predict the impact of tolerances on system performance. Furthermore, reducing an optical design’s sensitivity to manufacturing and alignment errors can help ensure that the system will perform as specified, be less expensive to manufacture, and can be assembled faster.

In a recent Synopsys tech talk, Dr. Weimin Shi explored the process of designing, optimizing, and tolerancing high-performance optical systems that work right the first time. Dr. Shi focused on unique approaches in CODE V and the RSoft Photonic Device Tools for both conventional and emerging optical systems to help designers create systems that perform as specified.

Balancing Performance and Cost in Optical System Design

A key theme of Dr. Shi's presentation was the importance of as-built system performance. This term refers to the performance of an optical system including fabrication and assembly errors after adjustment. Often, a system’s nominal performance does not accurately represent its real performance once it has been built. Therefore, it’s crucial to consider these potential errors and deviations in the design stage.

Dr. Shi emphasized that getting the design right the first time is essential. This involves understanding what could go wrong during the system’s fabrication, accurately modeling each fabrication error, and assessing its impact on as-built performance. Importantly, an aggregation of the impact of each error should be done to accurately predict the system’s as-built performance.

For each nominal optical design, several critical questions need to be addressed. Can the design be built based on a set of regular manufacturing tolerances? If the regular tolerances are not sufficient, how can the system's as-built performance be improved? If the system is too expensive to build due to tight tolerances, what are the alternatives?

Synopsys offers a suite of tools to help optical designers navigate these challenges. These tools can help reduce sensitivity of optical systems to manufacturing tolerances. Designers can determine the allowable dimensional variation of parameters and identify which parameters can be adjusted to meet two key goals: ensuring that the as-built performance satisfies design specifications with an acceptable production yield and minimizing manufacturing and assembly costs.

Tackling the Unique Challenges of Conventional and Emerging Optical Systems

Dr. Shi’s talk highlighted the unique challenges and requirements of different types of optical systems. Conventional optical systems have well-established design and fabrication methods, but they also have their own unique set of fabrication errors and performance limitations. On the other hand, design and fabrication techniques for emerging optical systems, such as metalenses, pose a fresh set of challenges.

CODE V is a comprehensive software package for the design, analysis, tolerancing, and fabrication support of both conventional and emerging optical systems. CODE V is used worldwide by organizations to design a wide range of systems and applications, including digital camera equipment, medical instruments, aerospace systems, telecommunication components, microlithographic stepper systems, and many more. Many of these companies and users chose CODE V for its advanced algorithms and features related to tolerancing, which can be used during design optimization to directly optimize for tolerance desensitization and achieve significant performance gains.

For example, CODE V includes a macro to quickly apply regular tolerances according to the current optical manufacturing industry standards and accurately predicts as-built performance, adjustment, and production yield. If the production yield is not good enough, CODE V can help improve the as-built performance and production yield by identifying critical elements that limit system performance.

Performance summary in CODE V | Synopsys
Wavefront Differential Tolerance Analysis | Synopsys

CODE V tolerancing feature (TOR) can accurately predict as-built performance, assembly adjustments and production yield.

Emerging optical systems like metalenses, which are constructed with meta-atoms, have unique challenges because of the high fidelity of shape and size required in their construction. Any deviation from the nominal design can affect the performance of the metasurface. To mitigate the impact of these manufacturing errors, Dr. Shi presented an innovative workflow using the RSoft Photonic Device Tools and Synopsys S-Litho. The workflow included the following steps:

  • Use MetaOptic Designer to develop a meta-atom library to achieve the desired metalens output
  • Simulate the meta-atoms in Synopsys S-Litho to confirm as-built system performance
  • Use MetaOptic Designer to optimize the metalens design using the meta-atom library to minimize the impact of manufacturing errors

Learn More About Synopsys Tools for High-Performance Optical Systems

Synopsys offers a comprehensive set of tolerancing analysis tools that can correctly model the impact of manufacturing errors, accurately predict as-built system performance and production yield, and guide users in targeting limiting tolerances to improve as-built performance.

These tools not only save production costs but also yield more robust as-built system performance. By offering a way to balance cost and performance, and by providing solutions tailored to both conventional and emerging optical systems, Synopsys empowers designers to create high-performance, cost-effective optical systems.

To learn more about Synopsys tolerancing capabilities:

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