Temperature sensing using Bragg gratings

Note

This tutorial requires the Luceda PDK for SiEPIC, which is downloaded together with the Luceda Academy samples.

In this tutorial, you will learn how to design a temperature sensor realized with a waveguide Bragg grating (WBG) and integrated on the silicon-on-insulator (SOI) material platform of the SiEPIC foundry.

First, we will explain why WBGs are useful for temperature sensing and you will learn their basic principles, such as how their unit cell structure (the basic building block of a WBG) determines the performance of the entire grating. You will then learn how to use Luceda IPKISS to calculate the properties of the unit cell - and thus the full WBG - at a fixed temperature. We will then optimize the unit cell configuration to attain maximum temperature sensitivity at a specific laser wavelength and use these calculations to generate a circuit simulation model. Finally, we will explain how we can connect the WBG sensor to the on-chip fiber couplers provided by the SiEPIC foundry, thus making the design ready for submission and fabrication. We will also provide an additional exercise in which you will have to use the above concepts to design a WBG that achieves the same functionality but is more robust to fabrication errors.

• 1. WBGs: why and how?
• 2. Designing a unit cell with IPKISS
• 3. Optimizing the temperature sensitivity
• 4. Creating the WBG layout and circuit model
• 5. Adding fiber couplers: the final working circuit