Learning Forum

[iqnlo]

Hi All

I am simulating fibre mode now and am a little bit confused about the difference between "E intensity" and "Ex, Ey, Ez." 

In fibre data sheet, we always say that the Mode Field Diameter is how many um. MFD is typically defined as the radial position where intensity falls to e-2 of the peak intensity. So MFD definition sounds like the definition of "effective mode area" in Lumerical.

However, could someone please explain the difference between the difference of each E component? And which E component is used for calculating the MFD (effective area)?

Thank you very much!

[Guilin Sun]

"E intensity" is the squareroot of abs(Ex)^2+abs(Ey)^2+abs(Ez)^2.

and "Ex, Ey, Ez" are the field components since E is a vector.

For effective area, please refer to this

The method you mentioned is significantly simplified. However there are several different definition formulas.