When silicon strip and slot waveguides are coated with a 50nm amorphous titanium dioxide (TiO₂) film, measured losses at a wavelength of 1.55 μm can be as low as (2 ± 1)dB/cm and (7 ± 2)dB/cm, respectively. We use atomic layer deposition (ALD), estimate the effect of ALD growth on the surface roughness, and discuss the effect on the scattering losses. Because the gap between the rails of a slot waveguide narrows by the TiO₂ deposition, the effective slot width can be back-end controlled. This is useful for precise adjustment if the slot is to be filled with, e. g., a nonlinear organic material or with a sensitizer for sensors applications.

© 2011 OSA

1. V. R. Almeida, Q. Xu, C. A. Barrios, and M. Lipson, “Guiding and confining light in void nanostructure,” Opt. Lett. 29, 1209–1211 (2004). [CrossRef] [PubMed]
2. Q. Xu, V. R. Almeida, R. R. Panepucci, and M. Lipson, “Experimental demonstration of guiding and confining light in nanometer-size low-refractive-index material,” Opt. Lett. 29, 1626–1628 (2004). [CrossRef] [PubMed]
3. C. A. Barrios, K. B. Gylfason, B. Sánchez, A. Griol, H. Sohlström, M. Holgado, and R. Casquel, “Slot-waveguide biochemical sensor,” Opt. Lett. 32, 3080–3082 (2007). [CrossRef] [PubMed]
4. P. Bienstman, “Label-free biosensing with a slot-waveguide-based ring resonator in silicon on insulator,” IEEE Photon. J. 1, 197–204 (2009). [CrossRef]
5. T. Alasaarela, A. Säynätjoki, T. Hakkarainen, and S. Honkanen, “Feature size reduction of silicon slot waveguides by partial filling using atomic layer deposition,” Opt. Eng. 48, 080502 (2009). [CrossRef]
6. T. Alasaarela, T. Saastamoinen, J. Hiltunen, A. Saynatjoki, A. Tervonen, P. Stenberg, M. Kuittinen, and S. Honkanen, “Atomic layer deposited titanium dioxide and its application in resonant waveguide grating,” Appl. Opt. 49, 4321–4325 (2010). [CrossRef] [PubMed]
7. J. Leuthold, W. Freude, J.-M. Brosi, R. Baets, P. Dumon, I. Biaggio, M. L. Scimeca, F. Diederich, B. Frank, and C. Koos, “Silicon organic hybrid technology - a platform for practical nonlinear optics,” Proc. IEEE 97, 1304–1316 (2009). [CrossRef]
8. C. Koos, P. Vorreau, T. Vallaitis, P. Dumon, W. Bogaerts, R. Baets, B. Esembeson, I. Biaggio, T. Michinobu, F. Diederich, W. Freude, and J. Leuthold, “All-optical high-speed signal processing with silicon-organic hybrid slot waveguides,” Nat. Photonics 3, 216 (2009). [CrossRef]
9. C. G. Poulton, C. Koos, M. Fujii, A. Pfrang, T. Schimmel, J. Leuthold, and W. Freude, “Radiation modes and roughness loss in high index-contrast waveguides,” IEEE J. Sel. Top. Quantum Electron. 12, 1306–1321 (2006). [CrossRef]
10. F. P. Payne and J. P. R. Lacey, “A theoretical analysis of scattering loss from planar optical waveguides,” Opt. Quantum Electron. 26, 977–986 (1994). [CrossRef]
11. K. K. Lee, D. R. Lim, H.-C. Luan, A. Agarwal, J. Foresi, and L. C. Kimerling, “Effect of size and roughness on light transmission in a Si/SiO2 waveguide: Experiments and model,” Appl. Phys. Lett. 77, 1617 (2000). [CrossRef]
12. K. K. Lee, D. R. Lim, L. C. Kimerling, J. Shin, and F. Cerrina, “Fabrication of ultralow-loss Si/SiO2 waveguides by roughness reduction,” Opt. Lett. 26, 1888–1890 (2001). [CrossRef]
13. D. Sparacin, S. Spector, and L. Kimerling, “Silicon waveguide sidewall smoothing by wet chemical oxidation,” J. Lightwave Technol. 23, 2455–2461 (2005). [CrossRef]
14. K. P. Yap, A. Delâge, J. Lapointe, B. Lamontagne, J. H. Schmid, P. Waldron, B. A. Syrett, and S. Janz, “Correlation of scattering loss, sidewall roughness and waveguide width in silicon-on-insulator (SOI) ridge waveguides,” J. Lightwave Technol. 27, 3999–4008 (2009). [CrossRef]
15. F. Grillot, L. Vivien, S. Laval, and E. Cassan, “Propagation loss in single-mode ultrasmall square silicon-on-insulator optical waveguides,” J. Lightwave Technol. 24, 891–896 (2006). [CrossRef]
16. J. Schrauwen, J. V. Lysebettens, T. Claes, K. D. Vos, P. Bienstman, D. V. Thourhout, and R. Baets, “Focused-ion-beam fabrication of slots in silicon waveguides and ring resonators,” IEEE Photon. Technol. Lett. 20, 2004–2006 (2008). [CrossRef]
17. F. Grillot, L. Vivien, S. Laval, D. Pascal, and E. Cassan, “Size influence on the propagation loss induced by sidewall roughness in ultrasmall SOI waveguides,” IEEE Photon. Technol. Lett. 16, 1661–1663 (2004). [CrossRef]
18. ePIXfab silicon photonics shuttle service, http://www.epixfab.eu/ .
19. FIMMWAVE by Photon Design, http://www.photond.com/ .
20. C. Koos, L. Jacome, C. Poulton, J. Leuthold, and W. Freude, “Nonlinear silicon-on-insulator waveguides for all-optical signal processing,” Opt. Express 15, 5976–5990 (2007). [CrossRef] [PubMed]

Appl. Opt.

• T. Alasaarela, T. Saastamoinen, J. Hiltunen, A. Saynatjoki, A. Tervonen, P. Stenberg, M. Kuittinen, and S. Honkanen, “Atomic layer deposited titanium dioxide and its application in resonant waveguide grating,” Appl. Opt. 49, 4321–4325 (2010). [CrossRef] [PubMed]

Appl. Phys. Lett.

• K. K. Lee, D. R. Lim, H.-C. Luan, A. Agarwal, J. Foresi, and L. C. Kimerling, “Effect of size and roughness on light transmission in a Si/SiO2 waveguide: Experiments and model,” Appl. Phys. Lett. 77, 1617 (2000). [CrossRef]

IEEE J. Sel. Top. Quantum Electron.

• C. G. Poulton, C. Koos, M. Fujii, A. Pfrang, T. Schimmel, J. Leuthold, and W. Freude, “Radiation modes and roughness loss in high index-contrast waveguides,” IEEE J. Sel. Top. Quantum Electron. 12, 1306–1321 (2006). [CrossRef]

IEEE Photon. J.

• P. Bienstman, “Label-free biosensing with a slot-waveguide-based ring resonator in silicon on insulator,” IEEE Photon. J. 1, 197–204 (2009). [CrossRef]

IEEE Photon. Technol. Lett.

• J. Schrauwen, J. V. Lysebettens, T. Claes, K. D. Vos, P. Bienstman, D. V. Thourhout, and R. Baets, “Focused-ion-beam fabrication of slots in silicon waveguides and ring resonators,” IEEE Photon. Technol. Lett. 20, 2004–2006 (2008). [CrossRef]
• F. Grillot, L. Vivien, S. Laval, D. Pascal, and E. Cassan, “Size influence on the propagation loss induced by sidewall roughness in ultrasmall SOI waveguides,” IEEE Photon. Technol. Lett. 16, 1661–1663 (2004). [CrossRef]

J. Lightwave Technol.

• D. Sparacin, S. Spector, and L. Kimerling, “Silicon waveguide sidewall smoothing by wet chemical oxidation,” J. Lightwave Technol. 23, 2455–2461 (2005). [CrossRef]
• K. P. Yap, A. Delâge, J. Lapointe, B. Lamontagne, J. H. Schmid, P. Waldron, B. A. Syrett, and S. Janz, “Correlation of scattering loss, sidewall roughness and waveguide width in silicon-on-insulator (SOI) ridge waveguides,” J. Lightwave Technol. 27, 3999–4008 (2009). [CrossRef]
• F. Grillot, L. Vivien, S. Laval, and E. Cassan, “Propagation loss in single-mode ultrasmall square silicon-on-insulator optical waveguides,” J. Lightwave Technol. 24, 891–896 (2006). [CrossRef]

Nat. Photonics

• C. Koos, P. Vorreau, T. Vallaitis, P. Dumon, W. Bogaerts, R. Baets, B. Esembeson, I. Biaggio, T. Michinobu, F. Diederich, W. Freude, and J. Leuthold, “All-optical high-speed signal processing with silicon-organic hybrid slot waveguides,” Nat. Photonics 3, 216 (2009). [CrossRef]

Opt. Eng.

• T. Alasaarela, A. Säynätjoki, T. Hakkarainen, and S. Honkanen, “Feature size reduction of silicon slot waveguides by partial filling using atomic layer deposition,” Opt. Eng. 48, 080502 (2009). [CrossRef]

Opt. Express

• C. Koos, L. Jacome, C. Poulton, J. Leuthold, and W. Freude, “Nonlinear silicon-on-insulator waveguides for all-optical signal processing,” Opt. Express 15, 5976–5990 (2007). [CrossRef] [PubMed]

Opt. Lett.

• V. R. Almeida, Q. Xu, C. A. Barrios, and M. Lipson, “Guiding and confining light in void nanostructure,” Opt. Lett. 29, 1209–1211 (2004). [CrossRef] [PubMed]
• Q. Xu, V. R. Almeida, R. R. Panepucci, and M. Lipson, “Experimental demonstration of guiding and confining light in nanometer-size low-refractive-index material,” Opt. Lett. 29, 1626–1628 (2004). [CrossRef] [PubMed]
• C. A. Barrios, K. B. Gylfason, B. Sánchez, A. Griol, H. Sohlström, M. Holgado, and R. Casquel, “Slot-waveguide biochemical sensor,” Opt. Lett. 32, 3080–3082 (2007). [CrossRef] [PubMed]
• K. K. Lee, D. R. Lim, L. C. Kimerling, J. Shin, and F. Cerrina, “Fabrication of ultralow-loss Si/SiO2 waveguides by roughness reduction,” Opt. Lett. 26, 1888–1890 (2001). [CrossRef]

Opt. Quantum Electron.

• F. P. Payne and J. P. R. Lacey, “A theoretical analysis of scattering loss from planar optical waveguides,” Opt. Quantum Electron. 26, 977–986 (1994). [CrossRef]

Proc. IEEE

• J. Leuthold, W. Freude, J.-M. Brosi, R. Baets, P. Dumon, I. Biaggio, M. L. Scimeca, F. Diederich, B. Frank, and C. Koos, “Silicon organic hybrid technology - a platform for practical nonlinear optics,” Proc. IEEE 97, 1304–1316 (2009). [CrossRef]

Other

• ePIXfab silicon photonics shuttle service, http://www.epixfab.eu/ .
• FIMMWAVE by Photon Design, http://www.photond.com/ .

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