Question about the Charge_distribution

Hi,

I have a question about the charge_distribution (np density attribute) in the attached file in https://kx.lumerical.com/t/ring-modulator-frequency-domain-with-forward-bias-pin-junction/31927.

I know we have calculated the np density distribution for different voltage in CHARGE. But later we enable the charge_distribution and export only one active waveguide ldf file after sweep. So what’s the corresponding voltage for this ldf file? And should we change it in the INTERCONNECT section for different applied DC voltage?

Thanks!

Hello @xiaona_zhu,

In this example, the .ldf file contains the waveguide properties of the unmodulated (V = 0) waveguide. This data is used for the waveguide element that corresponds to the active part of the ring. The change in effective index due to the modulation is stored in the “Delta_neff.txt” file that is loaded into the Optical Modulator element (OM_1) in INTERCONNECT:

To change the applied voltage, change the amplitude setting of the DC source attached to the OM_1 element. The OM_1 element will then apply the extra phase shift due to the modulation at that voltage.

I hope this helps. Let me know if you have any questions