Colorless directional coupler with dispersion engineered sub-wavelength structure Journal Articles uri icon

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  • Directional couplers are extensively used devices in integrated optics, but suffer from limited operational wavelength range. Here we use, for the first time, the dispersive properties of sub-wavelength gratings to achieve a fivefold enhancement in the operation bandwidth of a silicon-on-insulator directional coupler. This approach does not compromise the size or the phase response of the device. The sub-wavelength grating based directional coupler we propose covers a 100 nm bandwidth with an imbalance of ≤ 0.6 dB between its outputs, as supported by full 3D FDTD simulations.


  • Halir, R
  • Maese-Novo, A
  • Ortega-Moñux, A
  • Molina-Fernández, I
  • Wangüemert-Pérez, JG
  • Cheben, Pavel
  • Xu, D-X
  • Schmid, JH
  • Janz, S

publication date

  • June 4, 2012