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Proceedings Paper

Demultiplexer with blazed waveguide sidewall grating and subwavelength grating structure
Author(s): Przemek J. Bock; Pavel Cheben; Jens H. Schmid; Dan-Xia Xu; Siegfried Janz; Trevor J. Hall
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Paper Abstract

We propose an original diffraction grating demultiplexer (spectrometer) device with a very small footprint, designed for the silicon-on-insulator waveguide platform. The wavelength dispersive properties are provided by a second-order diffraction grating lithographically defined and etched in the sidewall of a curved Si waveguide. The grating is blazed to maximize the -1st order diffraction efficiency. The diffracted light is coupled into the silicon slab waveguide via an impedance matching sub-wavelength grating (SWG) graded-index (GRIN) anti-reflective interface. The waveguide is curved in order to focus the light onto the Rowland circle, where different wavelengths are intercepted by different output waveguides. The phase errors were substantially reduced using an apodized design with a chirped grating pitch, which assures a constant effective index along the grating length. The simulated crosstalk is -30 dB. The device has 15 channels with a spacing of 25 nm, thus a broadband operational bandwidth of 375 nm. Its performance approaches the diffraction limit. The device layout size is 90 μm × 50 μm, which is the smallest footprint yet reported for a mux/dmux device of a similar performance.

Paper Details

Date Published: 12 February 2008
PDF: 8 pages
Proc. SPIE 6896, Integrated Optics: Devices, Materials, and Technologies XII, 68960H (12 February 2008); doi: 10.1117/12.763357
Show Author Affiliations
Przemek J. Bock, Univ. of Ottawa (Canada)
National Research Council Canada (Canada)
Pavel Cheben, National Research Council Canada (Canada)
Jens H. Schmid, National Research Council Canada (Canada)
Dan-Xia Xu, National Research Council Canada (Canada)
Siegfried Janz, National Research Council Canada (Canada)
Trevor J. Hall, Univ. of Ottawa (Canada)

Published in SPIE Proceedings Vol. 6896:
Integrated Optics: Devices, Materials, and Technologies XII
Christoph M. Greiner; Christoph A. Waechter, Editor(s)

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