Guilin Sun
Ansys Employee

Unfortunately many optimizatio algorithms do not provide vectorial FOMs. The Particle Swarm Optimization Lumerical developed is a scalar optization, so you cannot direct optimize two FOMs. The suggestion I proposed can have both T1 and T2 about the same. You may need to figure it out where the loss goes, reflection or absorption? You can also invent your own FOM formulation and try if it works.

You could also borrow 3rd party vectorial optimization algorithm, or write your own.

If the FOM does not converge, it means you will need more number of generations. Yes, it needs to reach more parameter space in order to converge.