Learning Forum

[Ahmad Almohtadi]

Hello, I'm simulating an MZI sensor in INTERCONNECT and importing FDE solver data into waveguides that form the overall MZI. In terms of the MODE FDE simulation, I intend to use different combinations of thin film layers and gases to sense. Correct me if I'm wrong, but if I create a MODE simulation with the thin film and gas, the data that is used are the n,k info for propagation, which changes based on the interaction of the thin film with the gas, but the simulation does not consider any reactions between them (redox reactions in specific, leading to charge carrier changes), which affect their refractive indices. What can I do to include this interaction using the Lumerical suite? I am only familiar with MODE and INTERCONNECT simulations and I have basically done the simulation I have previously mentioned, but my purpose is to have a unique response of the MZI sensor that is specific to the interaction between the thin film and gas. Could anything be done with CHARGE or HEAT? If yes, please suggest how.

[Amrita Pati]

Hi Ahmad,

Since Lumerical solvers are photonic solvers, if the index change is due to a chemical reaction between the thin film and the gas then you won't be able to simulate this. But if you can get the perturbed index due to the interaction, then you can include this perturbed index to calculate the modal properties. Would you be able to confirm if the index change is due to a chemical interaction? Thank you!

Regards,
Amrita

[Ahmad Almohtadi]

Hello Amrita,

The basis of my use of the thin layer oxides (tin oxide, titanium oxide, zinc oxide, tungsten oxide....) is that those are the sensing materials used in electrical-based metal oxide sensors that are very common. Whether it be chemio-adsorption or physio-adsorption, the interaction of the gas with the oxide causes the change in resistivity that is measured by electrical means. I am trying to replicate this concept since a resistivity change also changes the refractive index of the material.

How can I go about getting the perturbed index due to the interaction using CHARGE? Even if it is not exactly replicating the interaction chemically. Would it be possible to just put the two material (metal oxide and gas) and see if there is any perturbation of the oxide index? (Assuming that the index change is NOT due to a chemical reaction). Also note that not all the oxides I am using are from the Lumerical Material Library but some are imported as n,k materials from the refractiveindex.info database.

Shown here is the sensing waveguide in MODE FDE.