Design of tapering one-dimensional photonic crystal ultrahigh-Q microcavities

Qin Chen, Duncan W E Allsopp

Research output: Contribution to journalArticlepeer-review


One-dimensional (1D) photonic crystal (PC) microcavities can be readily embedded into silicon-on-insulator waveguides for photonic integration. Such structures are investigated by 2D Finite-Difference Time-Domain method to identify designs with high transmission which is essential for device integration. On-resonance transmission is found to decrease with the increasing mirror pairs, however, the quality factor (Q) increases to a saturated value. The addition to the Bragg mirrors of tapered periods optimized to produce a cavity mode with a near Gaussian shaped envelope results in a major reduction in vertical loss. Saturated Q up to 2.4 106 is feasible if the internal tapers are properly designed. The effect of increasing transmission is also demonstrated in a structure with the external tapers.
Original languageEnglish
Pages (from-to)19-25
Number of pages7
JournalPhotonics and Nanostructures - Fundamentals and Applications
Issue number1
Publication statusPublished - Feb 2009


  • Time domain analysis
  • Method of moments
  • Crystal filters
  • Two dimensional
  • Microcavities
  • Photonic crystals
  • Q factor measurement
  • Mirrors
  • Crystal atomic structure


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