Learning Forum

[fachienchong]

hello,everyone.

i have met a question when i use the lumopt to design my device.

i have noticed that the Material index given in the example is 1.44/2.80(i.g. y branch inverse design),it means the egs_min/egs_max is 1.44/2.80.I do not change the value in my former design which works successfully.But i change it into 1.00/3.48(air/silicon),the first forward and adjoint simulation works successfully,When the program calculates the gradient, it gets stuck here.

how can i solve this, looking for answer.

[Guilin Sun]

It can be due to different reasons. Maybe the index contrast is too high to get correct gradient. Please try 2D FDTD or varFDTD first.

and you can also modify the online example to use your material system and see if it works.