Learning Forum

[mo_911]

Hello,

I am just wondering if there are any references such as published academic papers for the section "Effect of Joule Heating on Modulator Performance" on the page "PIN Mach-Zehnder modulator" at the link (https://support.lumerical.com/hc/en-us/articles/360042327854-PIN-Mach-Zehnder-modulator).

I understand how this simulation works on Lumerical, but would like to understand the mechanism in detail and hopefully find any experimental results that can support this discussion on the page.

I did not expect that the Joule-heating effect is so large that the applied voltage should be only 1 V or less. And I do not understand why only p-region is heated up. I can not find any reference papers that discuss this effect for PIN junction electro-optic modulators.

Thanks

[Khashayar Ghaffari]

Hi More detailed information about the calculations done for HEAT simulations, including the Joule effect is provided in this article. Additionally, here is another HEAT application example is that focuses on this effect.
The selected maximum voltage in the simulation is related to increased difficulty in obtaining convergence at higher current values; also performing the simulation in coupled mode adds another layer of difficulty for obtaining convergence. You should be able to further the convergence bias to some degree, by reducing the voltage step and increasing the global iteration limit in the advanced settings.
As you have suggested I can see that the reported temperature is not symmetric in the device. I will take a look and let you know if I have more information about this.
Best regards

[mo_911]

Hi Thank you for the info about HEAT simulations.
Actually, I had to change some parameters to get convergence at higher voltages as you mentioned in your post titled "Ansys Insight: Convergence issues in CHARGE", which was really helpful, though I can't find the post now.
Yes, I would like to understand why the reported temperature is not symmetric though the current should flow into the central core region symmetrically from both electrodes. According to my simulations, the temperature change is very important to calculate the refractive index change accurately. So, I would like to know if this is correct or not.
Best

[Khashayar Ghaffari]

Hi,
Good to know the post has been helpful to you. Here is the link.
Sounds good, I will keep you posted as I find more info about the asymmetry in reported temperature.
Best