A powerful, web-based tool for simulating optical pulse propagation in nonlinear fibers. This project solves the Generalized Nonlinear Schrödinger Equation (GNLSE) using the Split-Step Fourier Method (SSFM), allowing researchers and students to visualize complex nonlinear optical phenomena in real-time.

• High-Performance Simulation: Efficiently solves the GNLSE including:
  • Group Velocity Dispersion (GVD / $\beta_2$)
  • Third-Order Dispersion (TOD / $\beta_3$)
  • Fourth-Order Dispersion (FOD / $\beta_4$)
  • Self-Phase Modulation (SPM / Nonlinearity)
  • Stimulated Raman Scattering ($\tau_R$)
  • Self-Steepening Effect
• Interactive Visualization:
  • Time Domain: Pulse shape evolution.
  • Spectral Domain: Spectral broadening and shifting.
  • Spectrograms: X-FROG / Gating traces for complete pulse characterization.
  • Evolution Heatmaps: Visualize propagation dynamics along the fiber length.
• Modern UI: Responsive, glassmorphism-inspired design built with vanilla CSS and JavaScript for maximum performance and compatibility.
• Real-time Validation: Instant feedback on parameters like $N$, $\gamma$, and transform-limited pulse durations.

• Python 3.8 or higher
• pip (Python package installer)

1. Clone the repository:

   git clone https://github.com/visuphy/NLSEsolver.git
   cd NLSEsolver

2. Set up a Virtual Environment (Recommended):

   python -m venv venv
   # Windows
   venv\Scripts\activate
   # macOS/Linux
   source venv/bin/activate

3. Install dependencies:

   pip install -r requirements.txt

1. Start the Local Server: To run the tool without computational limits (recommended for local use):

   python run_local.py

   Note: This starts the server in development mode, allowing for higher grid resolution (N up to $2^{24}$).

2. Open in your browser: Navigate to http://localhost:5000/NLSEsolver/.

3. Run a Simulation:

   • Adjust the Grid settings (Time window, $N$ points).
   • Configure the Input Pulse (Shape, Wavelength $\lambda_0$, Duration, Energy).
   • Set Fiber Parameters ($\beta$ coefficients, $\alpha$, Length).
   • Toggle Nonlinear Effects (SPM, Raman, Steepening).
   • Click "Run simulation" to see the results.

• app.py: Main Flask application server. Handles routing and simulation requests.
• solver.py: Core physics engine containing the SSFM implementation and GNLSE logic.
• templates/: HTML templates (index.html for the main tool).
• static/: Static assets including style.css and JavaScript logic.
• requirements.txt: List of Python dependencies.

Contributions are welcome! Please feel free to submit a Pull Request.

This project is open-source and available under the MIT License.

• Hussein-Tofaili
• VisuPhy