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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 21 — Oct. 12, 2009
  • pp: 19120–19133

Sub-wavelength grating mode transformers in silicon slab waveguides

Przemek J. Bock, Pavel Cheben, Jens H. Schmid, André Delâge, Dan-Xia Xu, Siegfried Janz, and Trevor J. Hall  »View Author Affiliations

Optics Express, Vol. 17, Issue 21, pp. 19120-19133 (2009)

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We report on several new types of sub-wavelength grating (SWG) gradient index structures for efficient mode coupling in high index contrast slab waveguides. Using a SWG, an adiabatic transition is achieved at the interface between silicon-on-insulator waveguides of different geometries. The SWG transition region minimizes both fundamental mode mismatch loss and coupling to higher order modes. By creating the gradient effective index region in the direction of propagation, we demonstrate that efficient vertical mode transformation can be achieved between slab waveguides of different core thickness. The structures which we propose can be fabricated by a single etch step. Using 3D finite-difference time-domain simulations we study the loss, polarization dependence and the higher order mode excitation for two types (triangular and triangular-transverse) of SWG transition regions between silicon-on-insulator slab waveguides of different core thicknesses. We demonstrate two solutions to reduce the polarization dependent loss of these structures. Finally, we propose an implementation of SWG structures to reduce loss and higher order mode excitation between a slab waveguide and a phase array of an array waveguide grating (AWG). Compared to a conventional AWG, the loss is reduced from −1.4 dB to < −0.2 dB at the slab-array interface.

© 2009 OSA

OCIS Codes
(060.1810) Fiber optics and optical communications : Buffers, couplers, routers, switches, and multiplexers
(130.3120) Integrated optics : Integrated optics devices
(230.1950) Optical devices : Diffraction gratings

ToC Category:
Integrated Optics

Original Manuscript: June 1, 2009
Revised Manuscript: August 13, 2009
Manuscript Accepted: August 15, 2009
Published: October 8, 2009

Przemek J. Bock, Pavel Cheben, Jens H. Schmid, André Delâge, Dan-Xia Xu, Siegfried Janz, and Trevor J. Hall, "Sub-wavelength grating mode transformers in silicon slab waveguides," Opt. Express 17, 19120-19133 (2009)

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  1. S. M. Rytov, “Electromagnetic properties of a finely stratified medium,” Sov. Phys. JETP 2, 466–475 (1956).
  2. P. Lalanne and J.-P. Hugonin, “High-order effective-medium theory of subwavelength gratings in classical mounting: application to volume holograms,” J. Opt. Soc. Am. A 15(7), 1843–1851 (1998). [CrossRef]
  3. H. Kikuta, H. Toyota, and W. Yu, “Optical elements with subwavelength structured surfaces,” Opt. Rev. 10(2), 63–73 (2003). [CrossRef]
  4. C. F. R. Mateus, M. C. Y. Huang, L. Chen, C. J. Chang-Hasnain, and Y. Suzuki, “Broad-band mirror (1.12–1.62 μm) using a subwavelength grating,” IEEE Photon. Technol. Lett. 16, 1676–1678 (2004). [CrossRef]
  5. P. Cheben, D.-X. Xu, S. Janz, and A. Densmore, “Subwavelength waveguide grating for mode conversion and light coupling in integrated optics,” Opt. Express 14(11), 4695–4702 (2006). [CrossRef] [PubMed]
  6. P. Cheben, S. Janz, D.-X. Xu, B. Lamontagne, A. Delâge, and S. Tanev, “Highly efficient broad-band waveguide grating coupler with a sub-wavelength grating mirror,”, in Frontiers in planar lightwave circuit technology, S. Janz et al., eds. (Springer, 2006), 235–243.
  7. R. Halir, P. Cheben, S. Janz, D.-X. Xu, I. Molina-Fernández, and J. G. Wangüemert-Pérez, “Waveguide grating coupler with subwavelength microstructures,” Opt. Lett. 34(9), 1408–1410 (2009). [CrossRef] [PubMed]
  8. J. H. Schmid, P. Cheben, S. Janz, J. Lapointe, E. Post, and D.-X. Xu, “Gradient-index antireflective subwavelength structures for planar waveguide facets,” Opt. Lett. 32(13), 1794–1796 (2007). [CrossRef] [PubMed]
  9. J. H. Schmid, P. Cheben, S. Janz, J. Lapointe, E. Post, A. Delâge, A. Densmore, B. Lamontagne, P. Waldron and D.-X. Xu, “Subwavelength grating structures in silicon-on-insulator waveguides,” Advances in Optical Technologies: Special Issue on Silicon Photonics, 2008, Article ID 685489, doi:10.1155/2008/685489 (invited), (2008).
  10. P. Cheben, “Wavelength dispersive planar waveguide devices: echelle gratings and arrayed waveguide gratings,” in Optical waveguides: from theory to applied technologies, M. L. Calvo and V. Lakshminarayanan, eds. (CRC Press, 2007), 173–230.
  11. P. Cheben, A. Delâge, S. Janz, and D.-X. Xu, “Echelle gratings and arrayed waveguide gratings for WDM and spectral analysis,” in Advances in information optics and photonics, A.T. Friberg and R. Dändliker, eds. (SPIE Press, 2008), 599–632.
  12. C. R. Doerr and K. Okamoto, “Advances in silica planar lightwave circuits,” J. Lightwave Technol. 24(12), 4763–4789 (2006). [CrossRef]
  13. X. J. M. Leijtens, B. Kuhlow, and M. K. Smit, “Arrayed waveguide gratings,” in Wavelength filters in fiber optics, H. Venghaus, (Springer Verlag, 2006), 125–187.
  14. P. Cheben, A. Delâge, A. Densmore, M. Florjanczyk, S. Janz, B. Lamontagne, J. Lapointe, E. Post, J. Schmid and D.-X. Xu, “Silicon photonic waveguide structures and devices: From fundamentals to implementations in spectroscopy and biological sensing,” NATO Advanced Study Institute, (Springer 2009).
  15. P. Cheben, J. H. Schmid, A. Delâge, A. Densmore, S. Janz, B. Lamontagne, J. Lapointe, E. Post, P. Waldron, and D.-X. Xu, “A high-resolution silicon-on-insulator arrayed waveguide grating microspectrometer with sub-micrometer aperture waveguides,” Opt. Express 15(5), 2299–2306 (2007). [CrossRef] [PubMed]
  16. Y. Komai, H. Nagano, K. Okamoto, and K. Kodate, “Spectroscopic sensing using a visible arrayed-waveguide grating,” Proc. SPIE 5867, 91–102 (2005).
  17. J.-J. He, E. S. Koteles, B. Lamontagne, L. Erickson, A. Delâge, and M. Davies, “Integrated polarization compensator for WDM waveguide demultiplexers,” IEEE Photon. Technol. Lett. 11(2), 224–226 (1999). [CrossRef]
  18. P. Cheben, D.-X. Xu, S. Janz, A. Delâge, and D. Dalacu, “Birefringence compensation in silicon-on-insulator planar waveguide demultiplexers using a buried oxide layer,” Proc. SPIE 4997, 181–189 (2003). [CrossRef]
  19. P. J. Bock, P. Cheben, A. Delâge, J. H. Schmid, D.-X. Xu, S. Janz, and T. J. Hall, “Demultiplexer with blazed waveguide sidewall grating and sub-wavelength grating structure,” Opt. Express 16(22), 17616–17625 (2008). [CrossRef] [PubMed]
  20. S. Y. Chou, P. R. Krauss, and P. J. Renstrom, “Imprint lithography with 25-nanometer resolution,” Science 272(5258), 85–87 (1996). [CrossRef]
  21. P. Cheben, J. H. Schmid, P. J. Bock, D.-X. Xu, S. Janz, A. Delâge, J. Lapointe, B. Lamontagne, A. Densmore, and T. Hall, “Sub-wavelength nanostructures for engineering the effective index of silicon-on-insulator waveguides,” presented at the 11th International Conference on Transparent Optical Networks, Azores, Portugal, June 28 - July 2, 2009.
  22. J. H. den Besten, M. P. Dessens, C. G. P. Herben, X. J. M. Leijtens, F. H. Groen, M. R. Leys, and M. K. Smit, “Low-loss, compact, and polarization independent phasar demultiplexer fabricated by using a double-etch process,” IEEE Photon. Technol. Lett. 14(1), 62–64 (2002). [CrossRef]
  23. Y. P. Li, “Optical device having low insertion loss,” Patent 5745618 (1998).

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