How to convert from Lumerical simulations to OpticStudio and back

This tutorial illustrates how to convert information from OpticStudio into Lumerical’ s finite-difference eigenmode (FDE) solver. This can be useful for multi-stage cases in which one part of the system is a bulk optical system and a waveguide in others. In this example, we will look at the coupling from a focusing lens into a small silica fiber.

Author by Sahil Rajan


This tutorial illustrates how to convert information from OpticStudio into Lumerical Eigenmode solver software. This can be useful for multi-stage cases in which one part of the system is efficiently simulated in OpticStudio, and other parts (like waveguides, photonic crystals, etc.) require electromagnetic propagation tools. Lumerical’s finite-difference eigenmode (FDE) solver can be used to determine the physical properties of the optical modes supported by an arbitrary waveguide geometry.

In this example, we will look at the coupling from a focusing lens into a small silica fiber via the Lumerical Eigenmode solver software. This tutorial assumes some familiarity with the Lumerical software.

Getting the data from OpticStudio

In this section, we begin by opening up OpticStudio. Choose File...Open and then go to the {Zemax}\Samples\Physical Optics folder to open Fiber Coupling.zmx. You can select any of the analysis features, including the 2D layout to see how the rays focus on a point. 


Select Analysis...Physical Optics to see a 2 mm input waist Gaussian being focused on the image plane of the lens:


From here we can tell OpticStudio to output the beam files. Later we will need to import in Lumerical. Press the Settings option on the top of the Physical Optics Propagation window and then select the Display tab and click on the "Save Output Beam To:" option. Next, set the name of the file to be Fiber_output.zbf. Press OK. Please select the Use Polarization check box to define the vectorial beam. Without the Polarization, beam is scalar then needs to use script command to load the zbf file in Lumerical .


These files are typically saved in the {Zemax}\POP\BEAMFILES directory so you can find the file there.


Create the fiber structure for mode calculation

In this section, we will create the step-index fiber Open  Lumerical launcher and select a finite-difference eigenmode (FDE) solver.


The physical structure of step index fiber modelled are created using the STRUCTURES tab in the Layout Editor. Press the arrow on the STRUCTURES button and select CIRCLE from the pull-down menu.


Now edit the object properties.


Set the properties of the circle clad and core according to the following table.

Set Core properties.

tab property value


  x (μm) 0

y (μm)


z (μm) / z span (μm)

0 / 1.1

radius (μm)

Material   Object defined dielectric

Set Clad properties.

tab property value


  x (μm) 0

y (μm)


z (um) / z span (um)

0 / 1

radius (μm)

Material   Object defined dielectric



Index profile of Step Index fiber

We can now view the index profile as shown below. To view the index profile, click on mesh structure.


Import Zemax Beam File

This section describes the Finite Difference Eigenmode Solver (FDE) analysis component of MODE, once the physical structure and the simulation region have been defined. Now that we have created the structure, we can proceed with setting up the launch field. We have already exported Zemax beam file as fiber_output.ZBF. Now we will import the fiber_output.ZBF file in the Deck of Eigen solver Analysis Window.

Load the zbf file from Zemax LLC\Documents\Zemax\Samples\POP\BEAMFILES.


Calculate Modes

For viewing the field in Lumerical, you need to calculate the modes from Zemax beam File. Click Calculate Modes then we will have a Modal area. As we can see in the image below.



Overlap analysis

We will now calculate the overlap with an ideal Gaussian beam to determine the best spot-size we should use to couple with the fundamental modes in Zemax Beam file produced from OpticStudio. Choosing the "Overlap" tab results in the following screenshot. After clicking Calculate button calculates the overlap and the power coupling of the currently selected mode with the currently selected D-CARD. As the beam created in Lumerical is perfectly coupled for an 8-micron core diameter. As we see the overlapping between beam created in OpticStudio and ideal Gaussian beam (Beam launched in Lumerical), it is approximately 45 percent. The coupling to the higher order modes is exceedingly small.


Export Zemax Beam file to OpticStudio

Export the Mode as d-card in Deck. The d-card with better efficiency from Lumerical can be saved as Zemax Beam file. Now we import this beam to OpticStudio to check the coupling efficiency. 


Import new zemax beam file in OpticStudio

 Please import the new zemax beam file created in Lumerical back to OpticStudio. The waist size is reduced to 1.4 micron. 








Was this article helpful?
0 out of 0 found this helpful



Please sign in to leave a comment.