# EME solver cells - Simulation object

This topic applies to the Eigenmode Expansion solver in MODE.

As discussed in EME solver physics, the mesh along the propagation direction is defined by adding cells to the EME simulation region. An eigenmode simulation is carried out at the center x location of each cell to calculate all the modes supported at that cross section. Once the cells have been defined in the EME set up tab, they will appear as children of the EME solver region, as shown in the figure below.

To get the overall S matrix of the entire device, see the results section of Simulation - EME.

### Results returned

- MODE FIELDS: the spatial mode profiles of each mode in the current cell.
- NEFF: the effective indices of each mode in the current cell.
- OVERLAP_i_i-1: the overlap integrals between the set of modes in the current cell and the set of modes in the cell to the left of the current cell.
- OVERLAP_i_i+1: the overlap integrals between the set of modes in the current cell and the set of modes in the cell to the right of the current cell.
- PMATRIX: the power carried in each mode, in watts. In a device with no absorbing materials, no PML boundaries, the Pmatrix should be the identity matrix, one watt.
- S_i_i+1: S parameter matrix for all modes between cell i and i+1. Only available after fields have been propagated.