Quantum Dot Laser modelling in Interconnect

Dear community,

Is there any way to simulate QD laser dynamics through the Travelling Wave Laser Model (TWLM) in Interconnect? As far as I know, QD laser models have more than one carrier relations due to wetting layers, excited states, and the ground state. On the contrary, the TWLM refers only to one, so I was wondering if it’s possible to fit a complex QD model, given it’s known, to the simple TWLM? In any case, is it generally possible to simulate a QD laser in Interconnect?

Thanks for your time!

Hello @I.Skandalos,

Thank you for the question. I am not an expert on quantum dot lasers so I cannot say for sure if they can be modelled with the TWLM element. I believe that this should be possible, with the correct choices for the carrier recombination coefficients. I will have to discuss this with my colleagues and get back to you.

Let me know if you have any more questions.

Thanks a lot @kjohnson! I think that a translation needs to be done between QW rate/photon equation that TWLM uses, and a usually more complex model that corresponds to QD lasers. The problem is that in the TWLM page the rate equations are not explicitly mentioned, so should we assume that it follows exactly the equations that are given in the reference (1987 Lowery)?

Hello @I.Skandalos,

I have discussed this with a colleague, and we are still looking into this. We will consult our R&D team and get back to you when we have more answers. Sorry for the delay!

Hello @I.Skandalos,

We’ve spoken with the R&D team about this issue. To fully understand your application, we have a few follow up questions:

  • Can dot gain be defined as Lorentzian with peak magnitude linearly dependent on carrier density?
  • Is it important to be able to simulate inhomogeneous spectrum broadening due to variation of optical absorption/gain properties in different dots as well as spectral hole burning?
  • Is the question related to the edge emitting type of laser or VCSEL?

Hello @kjohnson,

Thanks a lot for your reply. Please, find my answers in the same order.

  • Gain can be defined as you describe. However, I’m mainly interested in introducing experimental data of gain curves for different carrier densities.

  • No, it’s not vital for the aforementioned to be taken into account.

  • I’m interested in edge emitting lasers.


Hello @I.Skandalos,

Sorry for the delay! I’ve passed on this info to our R&D team, and I’m waiting to hear back from them. I will let you know when I have more informations.

Hello @I.Skandalos,

Thank you for your patience! The R&D team suggested that because inhomogeneous current injection is not currently possible, the best approach would be to try a chain of TWLM and waveguide elements, where each TWLM corresponds to a quantum dot. This might work if there are not too many quantum dots in the cavity, however this method has not been tested so it is difficult to say.

If you would like, you can submit a feature request to the IX here for this type of model to be implemented: https://ix.lumerical.com/

Yes, that reference gives the basics of the model (though there are some extra features in our implementation), so the rate equations should be the same.