Guilin Sun
Ansys Employee

For fast help, please write your post later in the Photonics forum

Photonics (ansys.com)

It is not clear for me which product you are referring here. I guess it is from HEAT. The power scale in HEAT source is due to the fact that, in FDTD simulation, the result has been normalized to 1W, whereas in HEAT 1W is too high, and acutally it does not need 1W. So the scale factor of 1e-8 simply means the HEAT solver uses 10nw source.

Opto-thermal effect must be simulated separately with FDTD/MODE and HEAT.  When you use FDTD, please refer the example to output the absorbed power density. and to get temperature, you will need set proper scale in HEAT. 

Please post your questions in the Photonics forum. Thank you!