Interconnect example ring resonator

emm22_8emm22_8 Member Posts: 1

In the example here for coupled ring resonator filterhttps://support.lumerical.com/hc/en-us/articles/360042819293-Coupled-ring-resonator-filters. I was looking at the interconnect example optics_letters_vol26_n_12_jun2001_917_fig2_N5.icp. In this example, the total length of the ring, Lr=2997.92458 and Lc=1498.96229. How do we determine Lr and Lc? And what is nr, and why is it 100? 

Answers

  • GWANGGWANG Posts: 45Ansys Employee

    Hi emm22_8,


    Thank you for posting questions here. The explanation of the variables are on the same page above the examples. Lr is defined to get the specific ring FSR (given the group index), and Lc is defined to have as nearly equal as possible to an odd multiple (n) of a quarter-wavelength over the operating frequency band of the filter. Nr is just the multiple integer number of FSRs, and theoretically as long as it is an integer, it should be fine, the value used in the example is the one we calculated to give the best result given all the other parameters.


    Hope this can help.

  • emm22_8emm22_8 Posts: 2Member

    Hi Gwang,

    Thanks for the answer. The example is for center wavelength of 1552.52nm. How do you set the center wavelength?

  • GWANGGWANG Posts: 45Ansys Employee

    Hi emm22_8,


    This is the resonance wavelength of the ring, which is related to the effective index of the waveguide, and the total length of the ring.

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