Learning Forum

[Somnath Paul]

Hi,

I need to implement a time-dependent sweep of a laser frequency in Interconnect. The existing continuous wave (CWL) source does not offer a time-dependent sweep. I know the central frequency of the CWL can be swept using the sweep utility but the temporal sweeping rate can not be applied. Is there any way to control the frequency sweep and the sweep rate? 

Also, is there any way to modify the parameters of an existing component block by editing the setup codes? Are the setup codes accessible somehow?

[Kyle]

Hello,

Sweeping the frequency of a source is difficult in INTERCONNECT. This is because ths signals in INTERCONNECT are actually the amplitude of a carrier wave. Mathematically, if the total field is E(t) then the signal is the amplitude a(t) of a carrier wave at frequency "w":

E(t) = a(t)*exp(iwt)

The frequency of the source is really the frequency of the carrier wave, so this can't change during the simulation. Only the signal a(t) can change.

To sweep the frequency you will have to modulate the phase of the signal. Split the frequency of the carrier into a constant and a varying part:

w = w0 + w1(t)

The additional phase from the time varying frequency w1(t) is the integral of w1(t).

For example, with a linearly chirped signal the frequency is:

w = w0 + a*t

where "a" is a constant. The additional phase from the chirp is the integral of "a*t", (1/2)*a*t^2. This additional phase can be applied to the signal with a phase modulator element or a scripted optical source.

[Kyle]

No, you can't edit the code of the elements themselves. However, you can create your own scripted elements, though this is a very advanced feature and tends to take a lot of work. The documentation on scripted elements can be found here: Scripted Element - Element Library – Ansys Optics

[Somnath Paul]

The time-dependent frequency sweep is a very useful function and it would be helpful if this feature is added to CWL block.