DOI QR코드

DOI QR Code

Comparative Study of Uniform and Nonuniform Grating Couplers for Optimized Fiber Coupling to Silicon Waveguides

Lee, Moon Hyeok;Jo, Jae Young;Kim, Dong Wook;Kim, Yudeuk;Kim, Kyong Hon

  • Received : 2015.11.25
  • Accepted : 2016.02.19
  • Published : 2016.04.25

Abstract

We have investigated the ultimate limits of nonuniform grating couplers (NGCs) for optimized fiber coupling to silicon waveguides, compared to uniform grating couplers (UGCs). Simple grating coupler schemes, which can be fabricated in etching steps of the conventional complementary metal-oxide semiconductor (CMOS) process on silicon-on-insulator (SOI) wafers without forming any additional overlay structure, have been simulated numerically and demonstrated experimentally. Optimum values of the grating period, fill factor, and groove number for ultimate coupling efficiency of the NGCs are determined from finite-difference time-domain (FDTD) simulation, and confirmed with experimentally demonstrated devices by comparison to those for the UGCs. Our simulated results indicate that maximum coupling efficiency of NGCs is possible when the minimum pattern size is below 50 nm, but the experimental value for the maximum coupling efficiency is limited by the attainable fabrication tolerance in a practical device process.

Keywords

Grating couplers;Integrated optics devices

References

  1. Y. Tang, Z. Wang, L. Wosinski, U. Westergren, and S. He, “Highly efficient nonuniform grating coupler for silicon-on-insulator nanophotonic circuits,” Opt. Lett. 35, 1290-1292 (2010). https://doi.org/10.1364/OL.35.001290
  2. A. Mekis, S. Gloeckner, G. Masini, A. Narasimha, S. Sahni, and P. D. Dobbelaere, "A grating-coupler-enabled CMOS photonics platform," IEEE J. Select. Topics Quantum Electron. 7, 597-608 (2011).
  3. J. S. Orcutt, A. Khilo, C. W. Holzwarth, M. A. Popović, H. Li, J. Sun, T. Bonifield, R. Hollingsworth, F. X. Kärtner, H. I. Smith, V. Stojanović, and R. J. Ram, “Nanophotonic integration in state-of-the-art CMOS foundries,” Opt. Express 19, 2335-2346 (2011). https://doi.org/10.1364/OE.19.002335
  4. D. Taillaert, F. V. Laere, M. Ayre, W. Bogaerts, D. Van Thourhout, P. Bienstman, and R. Baets, “Grating couplers for coupling between optical fibers and nanophotonic waveguides,” Jpn. J. Appl. Phys. 45, 6071-6077 (2006). https://doi.org/10.1143/JJAP.45.6071
  5. D. Taillaert, P. Bienstman, and R. Baets, “Compact efficient broad band grating coupler for silicon-on-insulator waveguides,” Opt. Lett. 29, 2749-2751 (2004). https://doi.org/10.1364/OL.29.002749
  6. C. Li, H. Zhang, M. Yu, and G. Q. Lo, “CMOS-compatible high efficiency double-etched apodized waveguide grating coupler,” Opt. Express 21, 7868-7874 (2013). https://doi.org/10.1364/OE.21.007868
  7. L. He, Y. Liu, C. Galland, A. E. Lim, G. Lo, T. Baehr-Jones, and M. Hochberg, “A high-efficiency nonuniform grating coupler realized with 248-nm optical lithography,” IEEE Photon. Technol. Lett. 25, 1358-1361 (2013). https://doi.org/10.1109/LPT.2013.2265911
  8. W. S. Zaoui, A. Kunze, W. Vogel, M. Berroth, J. Butschke, F. Letzkus, and J. Burghartz, “Bridging the gap between optical fibers and silicon photonic integrated circuits,” Opt. Express 22, 1277-1286 (2014). https://doi.org/10.1364/OE.22.001277
  9. X. Chen, C. Li, C. K. Y. Fung, S. M. G. Lo, and H. K. Tsang, “Apodized waveguide grating couplers for efficient coupling to optical fibers,” IEEE Photon. Technol. Lett. 22, 1156-1158 (2010). https://doi.org/10.1109/LPT.2010.2051220
  10. A. Bozzola, L. Carroll, D. Gerace, I. Cristiani, and L. C. Andreani, “Optimising apodized grating couplers in a pure SOI platform to -0.5 dB coupling efficiency,” Opt. Express 23, 16289-16304 (2015). https://doi.org/10.1364/OE.23.016289
  11. A. Karimi, F. Emami, and N. Nozhat, “The effects of various apodization functions on the filtering characteristics of the grating-assisted SOI strip waveguides,” J. Opt. Soc. Korea 18, 101-109 (2014). https://doi.org/10.3807/JOSK.2014.18.2.101
  12. R. Waldhausl, B. Schnabel, P. Dannberg, E. B. Kley, A. Brauer, and W. Karthe, “Efficient coupling into polymer waveguides by gratings,” Appl. Opt. 36, 9383-9390 (1997). https://doi.org/10.1364/AO.36.009383
  13. D. Taillaert, W. Bogaerts, P. Bienstman, T. F. Krauss, P. V. Daele, I. Moerman, S. Verstuyft, K. D. Mesel, and R. Baets, “An out-of-plane grating coupler for efficienct butt-coupling between compact planar waveguides and single-mode fibers,” IEEE J. Quantum Electron. 38, 949-955 (2002). https://doi.org/10.1109/JQE.2002.1017613
  14. D. Vermeulen, S. Selvaraja, P. Verheyen, G. Lepage, W. Bogaerts, P. Absil, D. Van Thourhout, and G. Roelkens, “High-efficiency fiber-to-chip grating couplers realized using an advanced CMOS-compatible silicon-on-insulator platform,” Opt. Express 18, 18278-18283 (2010). https://doi.org/10.1364/OE.18.018278

Cited by

  1. Multiple layers of silicon–silica (Si–SiO2) pair onto silicon substrate towards highly efficient, wideband silicon photonic grating coupler vol.48, pp.10, 2016, https://doi.org/10.1007/s11082-016-0746-0
  2. Investigation on Periodically Surface-Corrugated Long-Period Gratings Inscribed on Photonic Crystal Fibers vol.12, pp.1, 2017, https://doi.org/10.1186/s11671-017-1968-1
  3. High-efficiency grating-couplers: demonstration of a new design strategy vol.7, pp.1, 2017, https://doi.org/10.1038/s41598-017-16505-z
  4. Theoretical analysis of simultaneously improving the light coupling efficiency and bandwidth between two separated grating couplers using integrated distributed Bragg reflectors vol.71, pp.10, 2017, https://doi.org/10.3938/jkps.71.665
  5. Theoretical analysis of simultaneously improving the light coupling efficiency and bandwidth between two separated grating couplers using integrated distributed Bragg reflectors vol.71, pp.10, 2017, https://doi.org/10.3938/jkps.71.647
  6. Analytic method for fast design of aperiodic fiber Bragg grating devices vol.57, pp.11, 2018, https://doi.org/10.1117/1.OE.57.11.117111
  7. High-extinction-ratio directional-coupler-type polarization beam splitter with a bridged silicon wire waveguide vol.43, pp.14, 2018, https://doi.org/10.1364/OL.43.003241
  8. Coupling strategies for silicon photonics integrated chips [Invited] vol.7, pp.2, 2019, https://doi.org/10.1364/PRJ.7.000201