Modeling the capacitance of an electro-optic modulator



I need to get an estimation for the value of the input capacitance of an electro-optic modulator? Can I do this using LUMERICAL?


You can calculate the input capacitance of an electro-optic modulator using DEVICE. DEVICE is Lumerical’s electrical solver that enables users to perform steady-state and transient simulations of charge and transport in semiconductors. The method used to calculate the capacitance will vary depending on the type and structure of the modulator. However, the basic concept is the same in all cases. You will have to apply an array of bias voltages to the electro-optic modulator in DEVICE and record the variation in charge. Then the rate of change in charge w.r.t. voltage will give you the capacitance. There are quite a few examples on our knowledge base that demonstrate the electrical simulation of different type of electro-optic modulators as well as capacitance calculations. Here are links to a few of them:

Mach-Zehnder modulator
Interleaved PN Junction Microring Modulator
SISCAP Modulator

Each of these examples calculate the capacitance of these modulators and you will notice that the measurement method varies depending on the modulator type. If you have any question regarding which approach suits your modulator of interest best then feel free to ask it here in the forum.

p.s. I am moving this post to the Applications category.