Abstract

For the compact integration of photonic circuits, wavelength-scale structures with a high index contrast are a key requirement. We developed a fabrication process for these nanophotonic structures in Silicon-on-insulator using CMOS processing techniques based on deep UV lithography. We have fabricated both photonic wires and photonic crystal waveguides and show that, with the same fabrication technique, photonic wires have much less propagation loss than photonic crystal waveguides. Measurements show losses of 0.24dB/mm for photonic wires, and 7.5dB/mm for photonic crystal waveguides. To tackle the coupling to fiber, we studied and fabricated vertical fiber couplers with coupling efficiencies of over 21%. In addition, we demonstrate integrated compact spot-size converters with a mode-to-mode coupling efficiency of over 70%.

© 2004 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |

  1. J. D. Joannopolous, R. Meade, and J.Winn, Photonic Crystals - Molding the Flow of Light (Princeton University Press, Princeton, N.J., 1995).
  2. �??SOITEC�??s Unibond(R) process,�?? Microelectronics Journal 27(4/5), R36 (1996).
  3. W. Bogaerts, V.Wiaux, D. Taillaert, S. Beckx, B. Luyssaert, P. Bienstman, and R. Baets, �??Fabrication of photonic crystals in silicon-on-insulator using 248-nm deep UV lithography,�?? IEEE J. Sel. Top. Quantum Electron. 8, 928�??934 (2002).
    [CrossRef]
  4. W. Bogaerts, V. Wiaux, P. Dumon, D. Taillaert, J. Wouters, S. Beckx, J. Van Campenhout, B. Luyssaert, D. Van Thourhout, and R. Baets, �??Large-scale production techniques for photonic nanostructures,�?? Proc. SPIE 5225, 101�??112 (2003).
    [CrossRef]
  5. J. Arentoft, T. Sondergaard, M. Kristensen, A. Boltasseva, M. Thorhauge, and L. Frandsen, �??Low-loss silicon-on-insulator photonic crystal waveguides,�?? Electron. Lett. 38, 274�??275 (2002).
    [CrossRef]
  6. M. Vaughan. The Fabry-Perot interferometer (Adam Hilger, Bristol, 1989).
  7. P. Dumon, W. Bogaerts, V. Wiaux, J. Wouters, S. Beckx, J. Van Campenhout, D. Taillaert, B. Luyssaert, P. Bienstman, D. Van Thourhout, and R. Baets, �??Low-loss SOI Photonic Wires and Ring Resonators Fabricated with Deep UV Lithography,�?? accepted for publication in Photonics Technology Letters (2004).
  8. T. Shoji, T. Tsuchizawa, T. Watanabe, K. Yamada, and H. Morita, �??Low loss mode size converter from 0.3 µm square Si waveguides to singlemode fibres,�?? Electron. Lett. 38, 1669�??1700 (2002).
    [CrossRef]
  9. D. Taillaert, W. Bogaerts, P. Bienstman, T. Krauss, P. Van Daele, I. Moerman, S. Verstuyft, K. De Mesel, and R. Baets, �??An out-of-plane grating coupler for efficient butt-coupling between compact planar waveguides and single-mode fibers,�?? IEEE J. Quantum Electron. 38, 949�??955, (2002).
    [CrossRef]
  10. M. M. Spühler, B. J. Offrein, G.-L. Bona, R. Germann, I. Massarek, and D. Erni, �??A Very Short Planar Silica Spot-Size Converter using a Nonperiodic Segmented Waveguide,�?? J. Lightwave Technol. 16, 1680 (1998).
    [CrossRef]

Electron. Lett. (2)

J. Arentoft, T. Sondergaard, M. Kristensen, A. Boltasseva, M. Thorhauge, and L. Frandsen, �??Low-loss silicon-on-insulator photonic crystal waveguides,�?? Electron. Lett. 38, 274�??275 (2002).
[CrossRef]

T. Shoji, T. Tsuchizawa, T. Watanabe, K. Yamada, and H. Morita, �??Low loss mode size converter from 0.3 µm square Si waveguides to singlemode fibres,�?? Electron. Lett. 38, 1669�??1700 (2002).
[CrossRef]

IEEE J. Quantum Electron. (1)

D. Taillaert, W. Bogaerts, P. Bienstman, T. Krauss, P. Van Daele, I. Moerman, S. Verstuyft, K. De Mesel, and R. Baets, �??An out-of-plane grating coupler for efficient butt-coupling between compact planar waveguides and single-mode fibers,�?? IEEE J. Quantum Electron. 38, 949�??955, (2002).
[CrossRef]

IEEE J. Sel. Top. Quantum Electron. (1)

W. Bogaerts, V.Wiaux, D. Taillaert, S. Beckx, B. Luyssaert, P. Bienstman, and R. Baets, �??Fabrication of photonic crystals in silicon-on-insulator using 248-nm deep UV lithography,�?? IEEE J. Sel. Top. Quantum Electron. 8, 928�??934 (2002).
[CrossRef]

J. Lightwave Technol. (1)

Microelectronics Journal (1)

�??SOITEC�??s Unibond(R) process,�?? Microelectronics Journal 27(4/5), R36 (1996).

Photonics Technology Letters (1)

P. Dumon, W. Bogaerts, V. Wiaux, J. Wouters, S. Beckx, J. Van Campenhout, D. Taillaert, B. Luyssaert, P. Bienstman, D. Van Thourhout, and R. Baets, �??Low-loss SOI Photonic Wires and Ring Resonators Fabricated with Deep UV Lithography,�?? accepted for publication in Photonics Technology Letters (2004).

Proc. SPIE (1)

W. Bogaerts, V. Wiaux, P. Dumon, D. Taillaert, J. Wouters, S. Beckx, J. Van Campenhout, B. Luyssaert, D. Van Thourhout, and R. Baets, �??Large-scale production techniques for photonic nanostructures,�?? Proc. SPIE 5225, 101�??112 (2003).
[CrossRef]

Other (2)

J. D. Joannopolous, R. Meade, and J.Winn, Photonic Crystals - Molding the Flow of Light (Princeton University Press, Princeton, N.J., 1995).

M. Vaughan. The Fabry-Perot interferometer (Adam Hilger, Bristol, 1989).

Supplementary Material (2)

» Media 1: GIF (289 KB)     
» Media 2: GIF (538 KB)     

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (11)

Fig. 1.
Fig. 1.

Fabrication process for photonic nanostructures in SOI using deep UV lithography and dry etching.

Fig. 2.
Fig. 2.

Linewidth on mask (1X) required to print a line with a given target linewidth at a certain exposure dose. The dose required to print a triangular lattice of 300nm holes with a 500nm pitch on target is also indicated.

Fig. 3.
Fig. 3.

Photonic crystal waveguides fabricated with deep UV lithography and dry etching. (a) a deeply-etched photonic crystal waveguide with trench defect, (b) the same structure with Silicon-only etch, (c) a racetrack resonator with Silicon-only etch

Fig. 4.
Fig. 4.

(a) Transmission spectrum of a Fabry-Perot cavity containing a 500nm wide photonic wire with a wire length Lpw of 10µm, 200µm and 1mm. The cavity is 5mm long and the mirrors are formed by the cleaved SOI facets. (b) Cavity loss, expressed in dB, as a function of wire length Lpw . The slope of the fitted line gives the propagation loss of the photonic wire in dB/mm.

Fig. 5.
Fig. 5.

Transmission spectrum of the racetrack resonator from Fig. 3(c) in the pass port and the drop port. The resonator has a Q of over 3000 and a coupling efficiency at resonance of 80%.

Fig. 6.
Fig. 6.

Propagation losses of a W1 photonic crystal waveguide with Silicon-only etch. The lattice has a pitch of 500nm and the holes a diameter of 320nm.

Fig. 7.
Fig. 7.

Fiber coupling structures in Silicon-on-insulator. (a) concept, (b. 239KB) Simulation of a 1-D grating, coupling from a waveguide to a fiber under a 10° angle.

Fig. 8.
Fig. 8.

SEM micrographs of a fiber coupling grating in Silicon-on-insulator. The grating etch is not as deep as the waveguide trenches.

Fig. 9.
Fig. 9.

Measurement of fiber coupling gratings. (a) measurement scheme, (b) coupling efficiency of a single fiber couples extracted from the fiber-to-fiber transmission measurement, compared to the simulation results.

Fig. 10.
Fig. 10.

Short spot-size converter between a 10µm wide ridge waveguide and a 500nm wide photonic wire. (a. 539KB) Simulation result, (b) a fabricated structure

Fig. 11.
Fig. 11.

Measurement of spot-size converters between a 10µm wide ridge waveguide and a 500nm wide photonic wire. (a.) Measurement scheme (b) fiber-to-fiber transmission measurement (using fiber couplers) of the structure from Fig. 10(b), compared to a 50µm linear taper.

Metrics