Necessary mode number in the MMI example


#1

In the MMI example of the EME solver, 50 modes were used in the MMI region. But actually, the MMI shown in the example file cannot support 50 modes, is it necessary to use so many modes?


All modes "leak" to Si substrate - can't analyze guided mode
#2

Hi. I am not an expert on this but here’s my two cents:

The EME solver calculates the coupling of the power in the input mode to all of the output modes to determine the overall coupling between input and output power. It is therefore important to make sure that you have included all the modes in the calculation. Setting the number of modes to a large number is thus safer since it will ensure that you are not missing any possible coupling between the input and an output mode. If you want to restrict the number of modes used, you can probably do a convergence test by gradually increasing the number of modes used and see when the value of the S parameters start to converge.


#3

Thank you for your reply and suggestion. I will run some convergence tests.