Reply To: Lumerical Interconnect Optical Fiber Model

[Guilin Sun]

For the first part, as I said prviously, it might losed a term delta_w or assumed that delta_w is unit with 1/s. So yes they cannot be directly added together without such delta_w. It uses delta_beta_2 with a purpose to distinguish it from delta_beta.

But seems Lumerical does not use beta1 (6.1.13).

From the Taylor series:

beta=beta0+beta1*delta_w+0.5*beta2*(delta_w)^2+...

where beta1=d(beta)/dw=1/vg.

so (beta1x-beta1y)/delta_w has the same unit as deta2. This is why I said there might missed a delta_w.

for the other post I have asked my colleage to help you as I am not expert for INTERCONNECT.