In this step, the field in the input plane will be set to a Gaussian distribution.

Step Action
1 In the layout, double click the input plane.

The Input Plane dialog box appears (see Figure 4).

BPM - Figure 4 Input Plafne dialog box – Global Data tab

Figure 4: Input Plafne dialog box – Global Data tab

2 Set the Starting Field to Gaussian. The polarization in Figure 2 was selected as quasi-TE. Therefore the Gaussian field is applied to Ex. The other component, Ey, is set to zero.
3 Set the Z position offset to 30.
4 Click the Input Fields 3D tab
5 Click Edit…   The Input Field dialog box appears.

BPM - Figure 5 Input Field dialog box

Figure 5: Input Field dialog box

6 Select the waveguide in the Waveguides list on the right hand side and click Add
7 Select the item in the Fields table on the left and click Edit.

The Field Properties dialog box appears (see Figure 6).

BPM - Figure 6 Field Properties

Figure 6: Field Properties

Check the fields have the following data

a.   Centre X: 0.0 b.   Center Y: 0.0

c.   Halfwidth X: 1.0

d.   Halfwidth Y: 0.5

8 Click OK.
9 Click OK to close the Input Field dialog box.
10 Click OK to close the Input Plane dialog box.
11 Save the project.
12 In the Layout Designer, select Simulation > Calculate 3D anisotropic Simulation

Anisotropic Simulation.

The Simulation Parameters dialog box appears.

BPM - Figure 7 Simulation Parameters

Figure 7: Simulation Parameters

13 Click Run… to start the anisotropic BPM simulator

BPM - Figure 8 Major field component, Ex, after 200 mm of propagation

Figure 8: Major field component, Ex, after 200 mm of propagation

Note: The Gaussian beam launched in the waveguide changes and reaches a stable configuration equal to that of one of the fundamental modes evaluated using the mode solver (refer to Lesson 17: Modal analysis of an anisotropic buried waveguide).

BPM - Figure 9 Minor Field component Ey after 200 m of propagation

Figure 9: Minor Field component Ey after 200 m of propagation