ring_resonator_coupler

Ring Resonator Coupler

Purpose: Simulates a ring resonator coupled to a waveguide using 3D FDTD to extract coupling coefficients, resonance characteristics, and field profiles for optimizing coupling efficiency.

What this module does

Models a ring resonator coupling system in 3D FDTD domain. Mention:

• device type: ring resonator coupled to waveguide
• simulation domain: FDTD
• what is being extracted: transmission spectra, coupling efficiency, resonance response, field profiles, gap and length sweep optimization

Quick start

1. Open and select a Lumerical template file from:

   user_inputs/lumerical_files/
   

   Available templates:

   • straight_ring_coupling_section.fsp - Ring resonator with straight waveguide coupling
   • coocentric_ring_coupling_section.fsp - Concentric ring resonator coupling
   • rectangular_ring_coupling_section.fsp - Rectangular ring resonator coupling

2. Set the template file index in:

   user_inputs/user_simulation_parameters.py
   

   Set file_index to select which template to use:

   • file_index = 0 for straight ring coupling
   • file_index = 1 for concentric ring coupling
   • file_index = 2 for rectangular ring coupling (required for length sweep)

3. Run the analysis scripts:

   python fields/getFields.py
   python index_profile/index_profile_2D.py
   python gap_sweep/getGapSweep.py
   python length_sweep/getLengthSweep.py
   python transmission/getFrequencyResponse.py
   

4. Results will be saved automatically under:

   FDTD/Results/ring_resonator_coupler/Figures/
   ├── Gap Sweep/
   ├── Length Sweep/
   └── (other result folders)
   

Simulation scripts

• fields/getFields.py : extract electromagnetic field profiles
• index_profile/index_profile_2D.py : generate refractive index profile visualization
• gap_sweep/getGapSweep.py : perform coupling gap parametric sweep
• length_sweep/getLengthSweep.py : perform coupling length parametric sweep
• transmission/getFrequencyResponse.py : extract transmission vs. wavelength spectrum

Run these scripts individually to perform different types of analysis on the ring resonator coupler

Inputs

Editable files are located in:

user_inputs/user_simulation_parameters.py

Set file_index to select which Lumerical template file to load:

• 0 = straight_ring_coupling_section.fsp
• 1 = concentric_ring_coupling_section.fsp
• 2 = rectangular_ring_coupling_section.fsp (required for length sweep)

All other simulation parameters (ring geometry, coupling gap, material properties, wavelength settings, sweep definitions) should be configured within the selected .fsp file.

Outputs

Results are saved automatically and may include:

• transmission spectra showing resonance peaks
• field plots showing resonator mode confinement
• refractive index profile plots
• gap and length sweep data for coupling optimization

Typical output location:

FDTD/Results/ring_resonator_coupler/

Folder structure

ring_resonator_coupler/
├── README.md
├── fields/
│   └── getFields.py
├── gap_sweep/
│   └── getGapSweep.py
├── index_profile/
│   └── index_profile_2D.py
├── length_sweep/
│   └── getLengthSweep.py
├── transmission/
│   └── getFrequencyResponse.py
└── user_inputs/
    ├── lumerical_files/
    │   ├── straight_ring_coupling_section.fsp
    │   ├── coocentric_ring_coupling_section.fsp
    │   └── rectangular_ring_coupling_section.fsp
    └── user_simulation_parameters.py

Notes

• Requires Lumerical installed and accessible via lumapi
• Scripts assume paths defined in config.py
• Designed to be run from the repository root
• Multiple ring geometries are supported; select the appropriate .fsp file for your configuration

Related modules

• FDTD/disk_resonator_coupler
• FDTD/coupled_ring_coupler
• MODE/directional_coupler

Status

• Verified
• Actively used
• Legacy or reference