Learning Forum

[megan.obrien]

Hi,

I am setting up an add drop ring resonator with bend radius 100 microns in Interconnect. I have set the propagation loss to be 1.6 dB/cm, which gives the round trip loss coefficient a = 0.988 (no other losses such as bend losses etc are taken into account for now). Using this, I get k1 = 0.19 and k2 = 0.2085 as my coupling coefficients. My group index from MODE is 2.399. 

Before running the simulation in Interconnect, I use Eq 22 to calculate what my Q-factor should be at a wavelength of 1.31 microns:

https://onlinelibrary.wiley.com/doi/abs/10.1002/lpor.201100017

And I get 15421.5. However, when I run the circuit in Interconnect, I get about 11000 for the Q-factor from the drop port. Why does it differ?

Thanks in advance!

[Guilin Sun]

It might have several different reasons: the formula has some assumptions that the simulation does not fulfill; the parameters you used might be different from simulation. for example, are r1, and r2 and power attentuation coefficient accurate and they are the same with simulation?

Please refer this post for more possible causes: 

Ansys Insight: Why my simulation result is different from published paper or experiment?

It might be easier to use the theory and simulation for smaller ring which you can use FDTD for verification. 

If the theoretical analysis can accurately predict final result, we would not need to simulate it.