Learning Forum

[Hannah Nguyen]

Dear,

I am working on enviroment of Lumerical Interconnect simulator. 

I worked with Laser TW (traveling wave laser model) and CW Laser. When I change frequency of CW Laser, the spectrum of TWLM is also changed. For example, I designed a TWLM with highest-power mode at 193 THz and the CWL was set at 193.1 THz; then I changed frequency of CWL to another value (maybe 193.5 THz) and the result is the frequency of highest-power mode was changed. I did not change any value of TWLM, I want it to fix all values I set. The spectrum of TWLM was measured by OSA in analyzer library. So, I do not know why it happenned and how to fix the spectrum of TWLM when changing frequency of CWL.

The following figure is the Schematic Design Environment.

Thank you. 

[Kyle]

Hello, in time domain simulations, the optical signals have a carrier frequency called the channel frequency. When you have two sources, the channel frequency will be the average of the source frequencies. So when you change the CWL frequency, the carrier frequency changes. The TWLM model might change with a different channel frequency, which is why the TWLM behaviour is changing. 

You can keep the channel frequency fixed by changing the "sample mode frequency band" property of the Root Element to "single" then manually selecting the channel frequency with the "sample mode center frequency" property:

[Hannah Nguyen]

Thank you so much for your reply and answer. I tried and it works now. Thanks again.