Subwavelength grating Fourier-transform interferometer array in silicon-on-insulator Academic Article uri icon

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  • A planar waveguide Fourier-transform spectrometer with densely arrayed Mach-Zehnder interferometers is demonstrated. Subwavelength gratings are used to produce an optical path difference without waveguide bends. The fabricated device comprises of an array of 32 Mach-Zehnder interferometers, which produce a spatial interferogram without any moving parts, yielding a spectral resolution of 50 pm and a free-spectral range of 0.78 nm. As a result of similar propagation losses in subwavelength grating waveguides and conventional strip waveguides, loss imbalance is minimized and high interferometic extinction ratio of −25 to −30 dB is obtained. Furthermore, phase and amplitude errors arising from normal fabrication variation are compensated by the spectral retrieval process using calibration measurements.


  • J Bock, Przemek
  • Cheben, Pavel
  • Velasco, Aitor
  • H Schmid, Jens
  • Delâge, André
  • Florjańczyk, Mirosław Mirek
  • Lapointe, Jean
  • Xu, DanXia
  • Vachon, Martin
  • Janz, S
  • Calvo, Maria

publication date

  • November 2013