🎯 Learning objectives

Set up a 1D slab waveguide in OghmaNano and compute TE/TM modes.
Interpret fundamental and higher-order modal profiles across wavelength.
Configure 2D mode solving: axis selection, mesh density, wavelength sampling.
Use eigenmode search settings (X/Y indices) to target specific modes.
Recognize interface discontinuities in TM and leakage/anti-guiding at long λ.

📦 Prerequisites

OghmaNano installed and working.
Basic familiarity with refractive index and guided modes.

⏱ Estimated time

Part A (1D TE/TM): 10–15 min
Part B (2D modes): 10–15 min
Part C (2D complex modes): 10–15 min

Slab waveguide mode solver

In this tutorial we compute the optical modes supported by slab waveguide structures in OghmaNano. We begin with a classic 1D three-layer stack (low-n / high-n core / low-n) and find transverse electric (TE) and transverse magnetic (TM) modes. We then extend to 2D mode searches with configurable mesh density and wavelength sampling, and show how to control the number of eigenmodes solved in the X and Y directions.

OghmaNano Optical ribbon showing the Optical mesh button highlighted. — Click the **Optical mesh** button in the **Optical ribbon** to open the *Optical mesh editor*. The button is highlighted in the red box above.

OghmaNano Optical Mesh Editor showing the Y-dimension mesh with wavelength points. — The **Optical Mesh Editor** showing the *1D mesh* in the Y direction. If you click on the **X button** in the toolbar, the X-dimension mesh can also be edited.

OghmaNano Optical Mesh Editor showing both X and Y dimension meshes with wavelength points. — After adding the **X mesh** and setting the number of mesh points to 20, both the X and Y meshes are defined, enabling a full 2D optical mesh.

1. Getting started: 1D slab (TE)

Open New simulation → Mode solvers and select the 1D slab waveguide example. Configure the layer stack (e.g., 500 nm / 500 nm / 500 nm) and refractive indices (n = 1 / 4 / 1 for cladding / core / cladding in this example). Set polarization to Transverse electric (TE).

OghmaNano Output tab showing the snapshots folder after a simulation has been run. — The **Output** tab after running the simulation. Here the **snapshots** folder is available — double-click it to open the snapshots viewer.

The Snapshots window displaying the calculated electric field distribution in the slab waveguide. By clicking the Add button and selecting Electric field, the 2D field profile is shown.

👉 Next step: Now continue to Part C for a more detailed OPV tutorial, including outputs, device layers, and advanced analysis.