Ansys Learning Forum Forums Discuss Simulation Photonics InterConnect setsparameter function, option “s coefficient” use : Reply To: InterConnect setsparameter function, option “s coefficient” use :

Kyle
Ansys Employee

Hello, the "s coefficients" option uses a ratio of two polynomials where each coefficient corresponds to a descending power of "s",  for example (A*s^2 + B*s + C)/(D*s^2 + E*s + F). For this function the matrix would have A,B,C in the first column and D,E,F in the second column.  If you want to make a function of the form A*s^2 + B*s + C you can set D=E=0 and F=1. The "coefficients" option works the same way.

The "s" corresponds to -2*pi*f*i. The negative sign comes from the sign convention Lumerical uses for the Fourier transform (the "physics" convention).