High Q one dimensional photonic crystal

skvarshneyskvarshney Member Posts: 6


I have been trying to replicate a paper on one dimensional photonic crystal of air holes etched in silicon as attached.

I have tried replicating structure given in figure 3 of the paper and attached the lumerical structure.I have used mode source of TE polarization and also the high Q analysis group to calculate the Q factor. The field have decayed in my simulation and auto shutoff level has reached 1E-5. So, there is no issue of the divergence.

The transmission spectrum that I got is not the same as given in figure 4 of the paper. I am getting all the peaks except the one that have high Q. Here, is the transmission spectrum that I have got.

I have done very fine meshing and run the simulation for long period of time. Still I am not able to get the high Q peak.

Please tell me what I am missing in my simulation.


  • trobertstroberts Posts: 61Ansys Employee

    Hello skvarshney,

    The results look pretty similar, but I would consider making the sim volume bigger in the transverse direction so that there is less interaction with the PML. Additionally make the transmission monitor as large as the source. This should help reduce the loss and bring the transmission up.

    The wavelength of the resonance will be very sensitive to the material parameters, given that the device is designed to be sensitive. Ensure the material parameters match between simulations. Also it can be helpful to use a mesh cell that is an integer divisor of the period of the holes so that each hole is meshed similarly.


  • skvarshneyskvarshney Posts: 8Member


    Thanks for the reply.

    I did the changes as said by you, but getting the same results as earlier. the peak should have Q factor of 10^7 whereas I am getting Q factor of 817.

    Please tell me how to improve my Q factor. I have used PML BC in all directions and increased the simulation volume.

    My PhC is modulated by varying its periodicity. How can mesh cell be an integer divisor of the period. Can you please tell me how I can mesh cell so that each holes is meshed similarly as I can they are not meshed similarly when dx=0.02um. will the meshing affect the result that much?

    Any advice would be of great help to me.

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