Design Best Practices
Patterns used by the top 1% of photonic engineers
Design Like an Expert
These best practices are distilled from thousands of successful photonic designs and interviews with industry-leading engineers. Following these patterns will help you create designs that are manufacturable, performant, and maintainable.
Design First
Plan before you place
Validate Early
Catch issues sooner
Iterate Fast
Use real-time feedback
1. Design Organization
Hierarchical Design
Organize your designs hierarchically using cells and subcircuits. This improves maintainability, enables reuse, and makes collaboration easier.
- Create reusable component cells
- Use meaningful names (e.g., ring_filter_1550nm)
- Group related components logically
- Keep hierarchy depth to 3-4 levels
- Document each cell's purpose
- Flat designs with hundreds of components
- Generic names (e.g., component_1, cell_2)
- Duplicating component geometry manually
- Mixing unrelated components in cells
- Deeply nested hierarchies (>6 levels)
Version Control
Treat your designs like code. Use version control, create branches for experiments, and document your changes.
# Recommended workflow main # Production-ready designs ├── feature/new-modulator # Experimental feature ├── optimize/ring-filter # Optimization branch └── fix/coupling-loss # Bug fix # Good commit messages "Add 4-channel AWG with 100GHz spacing" "Optimize ring radius for lower loss (0.3dB improvement)" "Fix waveguide routing in output section" # Bad commit messages "update" "changes" "WIP"
Pro Tip
Create named versions (milestones) before major changes. Usev1.0-initial,v2.0-optimized, etc.
2. Component Placement
Routing Best Practices
Waveguide Routing
- Respect minimum bend radius (typically 5-10um)
- Use S-bends for smooth direction changes
- Minimize total waveguide length
- Avoid sharp 90-degree corners
- Use tapers for width transitions
Spacing Rules
- Minimum 3um between parallel waveguides
- Allow space for metal routing
- Consider thermal crosstalk
- Leave room for testing structures
- Plan for I/O fiber spacing (127um/250um)
3. Performance Optimization
Optimization Workflow
Follow this systematic approach to optimize your designs for performance.
Baseline Simulation
Run initial simulation to establish performance baseline. Record all key metrics before optimization.
Identify Bottlenecks
Use field visualization to find loss sources. Common issues: mode mismatch, radiation loss, reflections.
Parameter Sweep
Use parameter sweeps to explore the design space. Focus on 2-3 key parameters at a time.
AI Optimization
Use FluxCore's AI to suggest improvements. Review suggestions but verify with simulation.
Validate & Document
Run final simulation with all optimizations. Document changes and improvement percentages.
4. Common Pitfalls
Mistakes to Avoid
1. Ignoring Fabrication Constraints
Design looks great in simulation but fails DRC or has manufacturing issues.
Solution: Enable DRC early and design with your foundry's PDK constraints from the start.
2. Over-Optimization for Single Wavelength
Design works perfectly at 1550nm but fails at nearby wavelengths.
Solution: Always simulate across your target bandwidth and check for wavelength sensitivity.
3. Ignoring Temperature Effects
Performance degrades significantly at operating temperature.
Solution: Include thermal simulations and design for temperature range.
4. Not Planning for Testing
No test structures or monitoring taps in the design.
Solution: Add test structures and monitor ports from the beginning.
5. Team Collaboration
Working in Teams
Communication
- Use comments to explain design decisions
- Tag teammates for review using @mentions
- Document assumptions and constraints
- Share simulation results with context
Workflow
- Define ownership for each subsystem
- Agree on interface specifications first
- Use design reviews before merging
- Create shared component libraries
Pre-Tapeout Checklist
Before submitting to a foundry, verify these items:
Design Verification
- All DRC errors resolved
- Layer mapping matches PDK
- All ports properly labeled
- Test structures included
Performance Verification
- Meets insertion loss spec
- Bandwidth requirements met
- Temperature sweep verified
- Polarization behavior confirmed
Next Steps
Related Guides
- Design Rule Checking- DRC documentation
- Export Formats- Manufacturing files
Advanced Features
- Real-Time Simulation- Live feedback
- AI Optimization- Automated improvement