I’m using the example on knowledge base:
There are few points that confused me.
- the clearance between rib edge and the boundary of high dopant regions does not agree with the reference  (actually, a big difference: 0.95um, 1.75um). How can the web claim that the simulation results well match the experimental results?
- the calculated series resistance from the slab in the electrical simulation was not used in RF simulation. In the RF simulation, a new assumed value 8 ohm-cm is used for both n- and p-doped slab instead. Why?
- In RF simulation, the PN junction was replaced by some lumped 2D sheet elements. But I don’t understand this statement:"The resistivity is set to 8 ohm-cm for both the n-type and p-type silicon, corresponding to a resistance of 1.6 ohm-cm for the TWM. " (from https://kb.lumerical.com/en/modulators_rf-simulation.html). In the example, the value for resistor was set as 8000 ohm and capacitance was set as 2e-16 F in the simulation file. How to convert these values for 2D sheet elements?
And, how to set the dimension of 2D element? I found that the dimensions of a 2D capacity and resistor also affect the propagation constant of RF signal.