Abstract

A polarization splitter and rotator (PSR) based on a tapered directional coupler with relaxed fabrication tolerance is proposed and demonstrated on the silicon-on-insulator platform. The device is simply constructed by parallel-coupling a narrow silicon waveguide with a linearly tapered wider waveguide. Compared to previously reported PSRs based on a normal directional coupler, which suffer from stringent requirements on the accuracy of the narrow waveguide width, the introduced tapered structure of the wide waveguide can be used to compensate the fabrication errors of the narrow waveguide. In addition, only a single step of exposure and etching is needed for the fabrication of the device. Similar high conversion efficiencies are experimentally demonstrated for a narrow waveguide width deviation of 14 nm with large tolerance to the coupler length.

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References

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  1. T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
    [CrossRef]
  2. E. Dulkeith, F. Xia, L. Schares, W. M. J. Green, and Y. A. Vlasov, “Group index and group velocity dispersion in silicon-on-insulator photonic wires,” Opt. Express14(9), 3853–3863 (2006).
    [CrossRef] [PubMed]
  3. S. T. Lim, C. E. Png, E. A. Ong, and Y. L. Ang, “Single mode, polarization-independent submicron silicon waveguides based on geometrical adjustments,” Opt. Express15(18), 11061–11072 (2007).
    [CrossRef] [PubMed]
  4. L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
    [CrossRef]
  5. W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, R. Baets, and E. Pluk, “A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires,” Opt. Express15(4), 1567–1578 (2007).
    [CrossRef] [PubMed]
  6. T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
    [CrossRef]
  7. H. Fukuda, K. Yamada, T. Tsuchizawa, T. Watanabe, H. Shinojima, and S. I. Itabashi, “Silicon photonic circuit with polarization diversity,” Opt. Express16(7), 4872–4880 (2008).
    [CrossRef] [PubMed]
  8. Y. Ding, L. Liu, C. Peucheret, J. Xu, H. Ou, K. Yvind, X. Zhang, and D. Huang, “Towards polarization diversity on the SOI platform with simple fabrication process,” IEEE Photon. Technol. Lett.23(23), 1808–1810 (2011).
    [CrossRef]
  9. L. Chen, C. R. Doerr, and Y. K. Chen, “Compact polarization rotator on silicon for polarization-diversified circuits,” Opt. Lett.36(4), 469–471 (2011).
    [CrossRef] [PubMed]
  10. H. Fukuda, K. Yamada, T. Tsuchizawa, T. Watanabe, H. Shinojima, and S. Itabashi, “Ultrasmall polarization splitter based on silicon wire waveguides,” Opt. Express14(25), 12401–12408 (2006).
    [CrossRef] [PubMed]
  11. H. Fukuda, K. Yamada, T. Tsuchizawa, T. Watanabe, H. Shinojima, and S. Itabashi, “Polarization rotator based on silicon wire waveguides,” Opt. Express16(4), 2628–2635 (2008).
    [CrossRef] [PubMed]
  12. L. Liu, Y. Ding, K. Yvind, and J. M. Hvam, “Efficient and compact TE-TM polarization converter built on silicon-on-insulator platform with a simple fabrication process,” Opt. Lett.36(7), 1059–1061 (2011).
    [CrossRef] [PubMed]
  13. L. Liu, Y. Ding, K. Yvind, and J. M. Hvam, “Silicon-on-insulator polarization splitting and rotating device for polarization diversity circuits,” Opt. Express19(13), 12646–12651 (2011).
    [CrossRef] [PubMed]
  14. Z. Wang and D. Dai, “Ultrasmall Si-nanowire-based polarization rotator,” J. Opt. Soc. Am. B25(5), 747–753 (2008).
    [CrossRef]
  15. J. Zhang, M. Yu, G. Lo, and D. L. Kwong, “Silicon waveguide based mode-evolution polarization rotator,” IEEE J. Sel. Top. Quantum Electron.16(1), 53–60 (2010).
    [CrossRef]
  16. D. Dai and J. E. Bowers, “Novel concept for ultracompact polarization splitter-rotator based on silicon nanowires,” Opt. Express19(11), 10940–10949 (2011).
    [CrossRef] [PubMed]
  17. A. S. Sudbo, “Film mode matching: a versatile numerical method for vector mode field calculations in dielectric waveguides,” Pure Appl. Opt.2(3), 211–233 (1993).
    [CrossRef]
  18. A. Taflove and S. C. Hagness, Computational Electrodynamics: The Finite-Difference Time-Domain Method, 2nd ed. (Artech House, 2000).
  19. FIMMWAVE/FIMMPROP, Photon Design Ltd, http://www.photond.com .
  20. S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
    [CrossRef]

2011

2010

J. Zhang, M. Yu, G. Lo, and D. L. Kwong, “Silicon waveguide based mode-evolution polarization rotator,” IEEE J. Sel. Top. Quantum Electron.16(1), 53–60 (2010).
[CrossRef]

S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
[CrossRef]

2008

2007

2006

2005

T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
[CrossRef]

2002

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

1993

A. S. Sudbo, “Film mode matching: a versatile numerical method for vector mode field calculations in dielectric waveguides,” Pure Appl. Opt.2(3), 211–233 (1993).
[CrossRef]

Ang, Y. L.

Baets, R.

S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
[CrossRef]

W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, R. Baets, and E. Pluk, “A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires,” Opt. Express15(4), 1567–1578 (2007).
[CrossRef] [PubMed]

Barwicz, T.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Bogaerts, W.

S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
[CrossRef]

W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, R. Baets, and E. Pluk, “A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires,” Opt. Express15(4), 1567–1578 (2007).
[CrossRef] [PubMed]

Bowers, J. E.

Cassan, E.

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

Chen, L.

Chen, Y. K.

Dai, D.

Ding, Y.

Doerr, C. R.

Dulkeith, E.

Dumon, P.

S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
[CrossRef]

W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, R. Baets, and E. Pluk, “A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires,” Opt. Express15(4), 1567–1578 (2007).
[CrossRef] [PubMed]

Dumont, B.

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

Fukuda, H.

Green, W. M. J.

Huang, D.

Y. Ding, L. Liu, C. Peucheret, J. Xu, H. Ou, K. Yvind, X. Zhang, and D. Huang, “Towards polarization diversity on the SOI platform with simple fabrication process,” IEEE Photon. Technol. Lett.23(23), 1808–1810 (2011).
[CrossRef]

Hvam, J. M.

Ippen, E. P.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Itabashi, S.

Itabashi, S. I.

Jun-Ichi, T.

T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
[CrossRef]

Kartner, F. X.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Koster, A.

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

Kwong, D. L.

J. Zhang, M. Yu, G. Lo, and D. L. Kwong, “Silicon waveguide based mode-evolution polarization rotator,” IEEE J. Sel. Top. Quantum Electron.16(1), 53–60 (2010).
[CrossRef]

Lardenois, S.

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

Laval, S.

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

Lim, S. T.

Liu, L.

Lo, G.

J. Zhang, M. Yu, G. Lo, and D. L. Kwong, “Silicon waveguide based mode-evolution polarization rotator,” IEEE J. Sel. Top. Quantum Electron.16(1), 53–60 (2010).
[CrossRef]

Morita, H.

T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
[CrossRef]

Ong, E. A.

Ou, H.

Y. Ding, L. Liu, C. Peucheret, J. Xu, H. Ou, K. Yvind, X. Zhang, and D. Huang, “Towards polarization diversity on the SOI platform with simple fabrication process,” IEEE Photon. Technol. Lett.23(23), 1808–1810 (2011).
[CrossRef]

Peucheret, C.

Y. Ding, L. Liu, C. Peucheret, J. Xu, H. Ou, K. Yvind, X. Zhang, and D. Huang, “Towards polarization diversity on the SOI platform with simple fabrication process,” IEEE Photon. Technol. Lett.23(23), 1808–1810 (2011).
[CrossRef]

Pluk, E.

Png, C. E.

Popovic, M. A.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Rakich, P. T.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Schares, L.

Selvaraja, S.

S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
[CrossRef]

Shinojima, H.

Shoji, T.

T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
[CrossRef]

Smith, H. I.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Socci, L.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Sudbo, A. S.

A. S. Sudbo, “Film mode matching: a versatile numerical method for vector mode field calculations in dielectric waveguides,” Pure Appl. Opt.2(3), 211–233 (1993).
[CrossRef]

Taillaert, D.

Takahashi, M.

T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
[CrossRef]

Tamechika, E.

T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
[CrossRef]

Tsuchizawa, T.

Van Thourhout, D.

S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
[CrossRef]

W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, R. Baets, and E. Pluk, “A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires,” Opt. Express15(4), 1567–1578 (2007).
[CrossRef] [PubMed]

Vivien, L.

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

Vlasov, Y. A.

Wang, Z.

Watanabe, T.

Watts, M. R.

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Xia, F.

Xu, J.

Y. Ding, L. Liu, C. Peucheret, J. Xu, H. Ou, K. Yvind, X. Zhang, and D. Huang, “Towards polarization diversity on the SOI platform with simple fabrication process,” IEEE Photon. Technol. Lett.23(23), 1808–1810 (2011).
[CrossRef]

Yamada, K.

Yu, M.

J. Zhang, M. Yu, G. Lo, and D. L. Kwong, “Silicon waveguide based mode-evolution polarization rotator,” IEEE J. Sel. Top. Quantum Electron.16(1), 53–60 (2010).
[CrossRef]

Yvind, K.

Zhang, J.

J. Zhang, M. Yu, G. Lo, and D. L. Kwong, “Silicon waveguide based mode-evolution polarization rotator,” IEEE J. Sel. Top. Quantum Electron.16(1), 53–60 (2010).
[CrossRef]

Zhang, X.

Y. Ding, L. Liu, C. Peucheret, J. Xu, H. Ou, K. Yvind, X. Zhang, and D. Huang, “Towards polarization diversity on the SOI platform with simple fabrication process,” IEEE Photon. Technol. Lett.23(23), 1808–1810 (2011).
[CrossRef]

IEEE J. Sel. Top. Quantum Electron.

T. Tsuchizawa, K. Yamada, H. Fukuda, T. Watanabe, T. Jun-Ichi, M. Takahashi, T. Shoji, E. Tamechika, S. Itabashi, and H. Morita, “Microphotonics devices based on silicon microfabrication technology,” IEEE J. Sel. Top. Quantum Electron.11(1), 232–240 (2005).
[CrossRef]

J. Zhang, M. Yu, G. Lo, and D. L. Kwong, “Silicon waveguide based mode-evolution polarization rotator,” IEEE J. Sel. Top. Quantum Electron.16(1), 53–60 (2010).
[CrossRef]

S. Selvaraja, W. Bogaerts, P. Dumon, D. Van Thourhout, and R. Baets, “Sub-nanometer linewidth uniformity in silicon nano-photonic waveguide devices using CMOS fabrication technology,” IEEE J. Sel. Top. Quantum Electron.16(1), 316–324 (2010).
[CrossRef]

IEEE Photon. Technol. Lett.

Y. Ding, L. Liu, C. Peucheret, J. Xu, H. Ou, K. Yvind, X. Zhang, and D. Huang, “Towards polarization diversity on the SOI platform with simple fabrication process,” IEEE Photon. Technol. Lett.23(23), 1808–1810 (2011).
[CrossRef]

J. Opt. Soc. Am. B

Nat. Photonics

T. Barwicz, M. R. Watts, M. A. Popovic, P. T. Rakich, L. Socci, F. X. Kartner, E. P. Ippen, and H. I. Smith, “Polarization-transparent microphotonic devices in the strong confinement limit,” Nat. Photonics1(1), 57–60 (2007).
[CrossRef]

Opt. Commun.

L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, and E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths,” Opt. Commun.210(1-2), 43–49 (2002).
[CrossRef]

Opt. Express

W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, R. Baets, and E. Pluk, “A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires,” Opt. Express15(4), 1567–1578 (2007).
[CrossRef] [PubMed]

E. Dulkeith, F. Xia, L. Schares, W. M. J. Green, and Y. A. Vlasov, “Group index and group velocity dispersion in silicon-on-insulator photonic wires,” Opt. Express14(9), 3853–3863 (2006).
[CrossRef] [PubMed]

S. T. Lim, C. E. Png, E. A. Ong, and Y. L. Ang, “Single mode, polarization-independent submicron silicon waveguides based on geometrical adjustments,” Opt. Express15(18), 11061–11072 (2007).
[CrossRef] [PubMed]

H. Fukuda, K. Yamada, T. Tsuchizawa, T. Watanabe, H. Shinojima, and S. I. Itabashi, “Silicon photonic circuit with polarization diversity,” Opt. Express16(7), 4872–4880 (2008).
[CrossRef] [PubMed]

L. Liu, Y. Ding, K. Yvind, and J. M. Hvam, “Silicon-on-insulator polarization splitting and rotating device for polarization diversity circuits,” Opt. Express19(13), 12646–12651 (2011).
[CrossRef] [PubMed]

H. Fukuda, K. Yamada, T. Tsuchizawa, T. Watanabe, H. Shinojima, and S. Itabashi, “Ultrasmall polarization splitter based on silicon wire waveguides,” Opt. Express14(25), 12401–12408 (2006).
[CrossRef] [PubMed]

H. Fukuda, K. Yamada, T. Tsuchizawa, T. Watanabe, H. Shinojima, and S. Itabashi, “Polarization rotator based on silicon wire waveguides,” Opt. Express16(4), 2628–2635 (2008).
[CrossRef] [PubMed]

D. Dai and J. E. Bowers, “Novel concept for ultracompact polarization splitter-rotator based on silicon nanowires,” Opt. Express19(11), 10940–10949 (2011).
[CrossRef] [PubMed]

Opt. Lett.

Pure Appl. Opt.

A. S. Sudbo, “Film mode matching: a versatile numerical method for vector mode field calculations in dielectric waveguides,” Pure Appl. Opt.2(3), 211–233 (1993).
[CrossRef]

Other

A. Taflove and S. C. Hagness, Computational Electrodynamics: The Finite-Difference Time-Domain Method, 2nd ed. (Artech House, 2000).

FIMMWAVE/FIMMPROP, Photon Design Ltd, http://www.photond.com .

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Figures (6)

Fig. 1
Fig. 1

Principle of the proposed polarization splitter and rotator based on a tapered DC. Light is launched from the narrow waveguide with a width w1 and is coupled to a wide waveguide tapered from w2a to w2b with tapering length L.

Fig. 2
Fig. 2

Effective indices of the TE0, TE1 and TM0 modes of an air-clad SOI waveguide as a function of the waveguide width w for a waveguide height h = 250 nm.

Fig. 3
Fig. 3

3-D FDTD simulations of the tapered DC for TE0 light injected into the narrow waveguide. (a) and (c) w1 = 340 nm, w2a = 500 nm, w2b = 660 nm, L = 80 μm. (b) and (d) w1 = 340 nm, w2a = 500 nm, w2b = 800 nm, L = 80 μm. The resolution of the 3-D FDTD space grid is ∆x = 20 nm, ∆y = 50 nm, ∆z = 50 nm.

Fig. 4
Fig. 4

Simulated power conversion coefficient T c T E 0 T M 0 as a function of coupling length L for different width deviations ∆w and coupling gap g (a), and as a function of width deviation ∆w for different L and g (b) for both tapered and normal DCs. The operation wavelength is 1550 nm.

Fig. 5
Fig. 5

Microscope picture of the fabricated tapered DC and scanning electron microscope (SEM) images of the starting and ending coupling areas of the tapered DC.

Fig. 6
Fig. 6

(a) Measured power conversion coefficient T c T E 0 T M 0 for different w1 with coupling length L = 140 μm. (b) Measured T c T E 0 T M 0 at the peak wavelength of 1540 nm as a function of w1 for L = 140 μm. (c) Measured T c T E 0 T M 0 for different tapering lengths L for w1 = 324 nm.

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