NumBAT - The Numerical Brillouin Analysis Tool - User Guide

Release date: 01 August 2025

Contents:

• 1. Introduction to NumBAT
  • 1.1. Introduction
  • 1.2. Goals
  • 1.3. Development team
  • 1.4. Citing NumBAT
  • 1.5. Contributing to NumBAT
  • 1.6. Seeking assistance
  • 1.7. Release notes
  • 1.8. About our mascot
  • 1.9. Acknowledgements
• 2. Background theory
  • 2.1. What does NumBAT actually calculate?
  • 2.2. The method of solution in NumBAT
  • 2.3. Suggested reading on SBS and opto-elastic interactions in nanophotonics
• 3. Installing NumBAT
  • 3.1. Installing on Linux
  • 3.2. Installing on MacOS
  • 3.3. Installing on Windows
  • 3.4. Seeking help with building NumBAT
  • 3.5. Building the documentation
• 4. Basic Usage
  • 4.1. A First Calculation
  • 4.2. General Simulation Procedures
  • 4.3. Script Structure
• 5. Tutorial
  • 5.1. Some Key Symbols
  • 5.2. Elementary Tutorials
• 6. Materials, waveguides and meshing
  • 6.1. Materials
  • 6.2. Waveguide Geometries
  • 6.3. User-defined waveguide geometries
  • 6.4. Mesh parameters
  • 6.5. Viewing the mesh
• 7. Properties of bulk crystal elastic modes
  • 7.1. Tutorial 9a - Bulk elastic anisotropy
  • 7.2. Introduction to piezoelectric properties with lithium niobate
  • 7.3. Piezolectric properties of lithium niobate
  • 7.4. Other material comparisons
• 8. Advanced Tutorials
  • 8.1. Tutorial 11 – Two-layered ‘Onion’
  • 8.2. Tutorial 12 – Validating the calculation of the EM dispersion of a two-layer fibre
  • 8.3. Tutorial 13 – Validating the calculation of the dispersion of an elastic rod in vacuum
  • 8.4. Tutorial 14 – Multilayered ‘Onion’
  • 8.5. Tutorial 15 – Coupled waveguides
• 9. JOSA-B Tutorial Paper
  • 9.1. Introduction
• 10. Additional Literature Examples
  • 10.1. Example 1 – BSBS in a silica rectangular waveguide
  • 10.2. Example 2 – BSBS in a rectangular silicon waveguide
  • 10.3. Example 3 – BSBS in a tapered fibre - scanning widths
  • 10.4. Example 4 – FSBF in a waveguide on a pedestal
  • 10.5. Example 5 – FSBF in a waveguide without a pedestal
  • 10.6. Example 6 – BSBS self-cancellation in a tapered fibre (small fibre)
  • 10.7. Example 6b – BSBS self-cancellation in a tapered fibre (large fibre)
  • 10.8. Example 7 – FSBF in a silicon rib waveguide
  • 10.9. Example 8 – Intermodal FSBF in a silicon waveguide
  • 10.10. Example 9 – BSBS in a chalcogenide rib waveguide
  • 10.11. Example 10 – SBS in the mid-infrared
• 11. Additional details
  • 11.1. User plot preferences
• 12. Numerical formulation of the finite element problems
  • 12.1. Introduction
  • 12.2. Elastic modal problem
  • 12.3. Electromagnetic problem
• 13. Python Interface API
  • 13.1. numbat module
  • 13.2. materials module
  • 13.3. voigt module
  • 13.4. modes module
  • 13.5. structure module
  • 13.6. modecalcs module
  • 13.7. integration module
  • 13.8. plotting module
• 14. References
• 15. Indices and tables