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Ultracompact optical buffers on a silicon chip

Nature Photonics volume 1, pages 65–71 (2007)Cite this article

Abstract

On-chip optical buffers based on waveguide delay lines might have significant implications for the development of optical interconnects in computer systems. Silicon-on-insulator (SOI) submicrometre photonic wire waveguides are used, because they can provide strong light confinement at the diffraction limit, allowing dramatic scaling of device size. Here we report on-chip optical delay lines based on such waveguides that consist of up to 100 microring resonators cascaded in either coupled-resonator or all-pass filter (APF) configurations. On-chip group delays exceeding 500 ps are demonstrated in a device with a footprint below 0.09 mm2. The trade-offs between resonantly enhanced group delay, device size, insertion loss and operational bandwidth are analysed for various delay-line designs. A large fractional group delay exceeding 10 bits is achieved for bit rates as high as 20 Gbps. Measurements of system-level metrics as bit error rates for different bit rates demonstrate error-free operation up to 5 Gbps.

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Figure 1: Scanning electron micrographs of resonantly enhanced optical delay lines based on photonic-wire waveguides.
Figure 2: Optical characterization of losses in waveguides, bends and cascaded ring resonators in an APF configuration.
Figure 3: Optical characterization of losses and phase in cascaded ring resonators in a CROW configuration.
Figure 4: Measured time delay of different types of delay lines at varying bit rates.
Figure 5: BER and eye diagram measurements.

References

  1. Semiconductor Industry Association. International Technology Roadmap for Semiconductors (ITRS), Interconnect Chapter (Semiconductor Industry Association, 2005). Available at http://www.itrs.net.

  2. Luijten, R., Minkenberg, C., Hemenway, R., Sauer, M. & Grzybowski, R. Viable opto-electronic HPC interconnect fabrics. Proceedings of the ACM/IEEE SC05 Supercomputer 2005 Conference, 8–16 (2005).

  3. Hau, L. V. et al. Light speed reduction to 17 metres per second in an ultracold atomic gas. Nature 397, 594–598 (1999).

    Article  ADS  Google Scholar 

  4. Bajcsy, M., Zibrov, A. S. & Lukin, M. D. Stationary pulses of light in an atomic medium. Nature 426, 638–641 (2003).

    Article  ADS  Google Scholar 

  5. Okawachi, Y. et al. Tunable all-optical delays via Brillouin slow light in an optical fiber. Phys. Rev. Lett. 94, 153902 (2005).

    Article  ADS  Google Scholar 

  6. Boyd, R. W., Gauthier, D. J., Gaeta, A. L. & Willner, A. E. Maximum time delay achievable on propagation through a slow-light medium. Phys. Rev. A 71, 023801 (2005).

    Article  ADS  Google Scholar 

  7. Tucker, R. S., Ku, P.-C. & Chang-Hasnain, C. J. Slow-light optical buffers: capabilities and fundamental limitations. J. Lightwave Technol. 23, 4046–4066 (2005).

    Article  ADS  Google Scholar 

  8. Khurgin, J. B. Optical buffers based on slow light in electromagnetically induced transparent media and coupled resonator structures: comparative analysis. J. Opt. Soc. Am. B 22, 1062–1074 (2005).

    Article  ADS  Google Scholar 

  9. Rasras, M. S. et al. Integrated resonance-enhanced variable optical delay lines. IEEE Photon. Technol. Lett. 17, 834–836 (2005).

    Article  ADS  Google Scholar 

  10. Vlasov, Y. A., O'Boyle, M., Hamann, H. F. & McNab, S. J. Active control of slow light on a chip with photonic crystal waveguides. Nature 438, 65–69 (2005).

    Article  ADS  Google Scholar 

  11. Yariv, A., Xu, Y., Lee, R. K. & Scherer, A. Coupled-resonator optical waveguide: A proposal and analysis. Opt. Lett. 24, 711–713 (1999).

    Article  ADS  Google Scholar 

  12. Heebner, J. E., Boyd, R. W. & Park, Q. Slow light, induced dispersion, enhanced nonlinearity, and optical solitons in a resonator-array waveguide. Phys. Rev. E 65, 036619 (2002).

    Article  ADS  Google Scholar 

  13. Scalora, M., Flynn, R. J., Reinhardt, S. B. & Fork, R. L. Ultrashort pulse propagation at the photonic band-edge — large tunable group delay with minimal distortion and loss. Phys. Rev. E 54, R1078 (1996).

    Article  ADS  Google Scholar 

  14. Yanik, M. F. & Fan, S. Stopping light all-optically. Phys. Rev. Lett. 92, 083901 (2004).

    Article  ADS  Google Scholar 

  15. Maleki, L., Matsko, A. B., Savchenkov, A. A. & Ilchenko, V. S. Tunable delay line with interacting whispering-gallery-mode resonators. Opt. Lett. 29, 626–628 (2004).

    Article  ADS  Google Scholar 

  16. Lenz, G., Eggleton, B. J., Madsen, C. K. & Slusher, R. E. Optical delay lines based on optical filters. IEEE J. Quantum Electron. 37, 525–532 (2001).

    Article  ADS  Google Scholar 

  17. Xu, Q. et al. Experimental realization of an on-chip all-optical analogue to electromagnetically induced transparency. Phys. Rev. Lett. 96, 123901 (2006).

    Article  ADS  Google Scholar 

  18. Little, B. E. et al. Ultra-compact Si/SiO2 microring resonator optical channel dropping filters. IEEE Photon. Technol. Lett. 10, 549–551 (1998).

    Article  ADS  MathSciNet  Google Scholar 

  19. Madsen, C. K. & Lenz, G. Optical all-pass filters for phase response design with applications for dispersion compensation. IEEE Photon. Technol. Lett. 10, 994–996 (1998).

    Article  ADS  Google Scholar 

  20. Little, B. E. et al. Very high-order microring resonator filters for WDM applications. IEEE Photon. Technol. Lett. 16, 2263–2265 (2004).

    Article  ADS  Google Scholar 

  21. Barwicz T. et al. Microring-resonator-based add–drop filters in SiN: fabrication and analysis. Opt. Express 12, 1437–1442 (2004).

    Article  ADS  Google Scholar 

  22. Barwicz, T. et al. Fabrication of add–drop filters based on frequency-matched microring resonators. J. Lightwave Technol. 24, 2207–2218 (2006).

    Article  ADS  Google Scholar 

  23. Xu, Q., Schmidt, B., Pradhan, S. & Lipson, M. Micrometre-scale silicon electro-optic modulator. Nature 435, 325–327 (2005).

    Article  ADS  Google Scholar 

  24. Baehr-Jones, T., Hochberg, M., Walker, C. & Scherer, A. High-Q ring resonators in thin silicon-on-insulator. Appl. Phys. Lett. 85, 3346–3348 (2004).

    Article  ADS  Google Scholar 

  25. Xia, F., Sekaric, L. & Vlasov, Y. A. Mode conversion losses in silicon-on-insulator photonic wire based racetrack resonators. Opt. Express 14, 3872–3886 (2006).

    Article  ADS  Google Scholar 

  26. Poon, J. K. S., Zhu, L., DeRose, G. A. & Yariv, A. Polymer microring coupled resonator optical waveguides. IEEE J. Lightwave Technol. 24, 1843–1849 (2006).

    Article  ADS  Google Scholar 

  27. Poon, J. K. S., Zhu, L., DeRose, G. A. & Yariv, A. Transmission and group delay of microring coupled-resonator optical waveguides. Opt. Lett. 31, 456–458 (2006).

    Article  ADS  Google Scholar 

  28. Poon, J. K. S., Scheuer, J., Xu, Y. & Yariv, A. Designing coupled-resonator optical waveguide delay lines. J. Opt. Soc. Am. B 21, 1665–1673 (2004).

    Article  ADS  Google Scholar 

  29. Xia, F., Sekaric, L., O'Boyle, M. & Vlasov, Y. A. Coupled resonator optical waveguides based on silicon-on-insulator photonic wires. Appl. Phys. Lett. 89, 041122 (2006).

    Article  ADS  Google Scholar 

  30. Pozzi, F. et al. Integrated high order filters in AlGaAs waveguides with up to eight side-coupled racetrack microresonators. Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference, paper CWK2 (2006).

  31. Dumon, P. et al. Low-loss SOI photonic wires and ring resonators fabricated with deep UV lithography. IEEE Photon. Technol. Lett. 16, 1328–1330 (2004).

    Article  ADS  Google Scholar 

  32. Vlasov, Y. A. & McNab, S. J. Losses in single-mode silicon-on-insulator strip waveguides and bends. Opt. Express 12, 1622–1631 (2004).

    Article  ADS  Google Scholar 

  33. Bogaerts, W. et al. Nanophotonic waveguides in silicon-on-insulator fabricated with CMOS Technology. IEEE J. Lightwave Technol. 23, 401–412 (2005).

    Article  ADS  Google Scholar 

  34. Dulkeith, E. et al. Group index and group velocity dispersion in silicon-on-insulator photonic wires. Opt. Express 14, 3853–3863 (2006).

    Article  ADS  Google Scholar 

  35. Tsuchizawa, T. et al. Microphotonics devices based on silicon microfabrication technology, IEEE J. Sel. Top Quantum Electron. 11, 232–239 (2005).

    Article  ADS  Google Scholar 

  36. Sakai, A., Fukazawa, T. & Baba, T. Estimation of polarization crosstalk at a micro-bend in Si-photonic wire waveguide. J. Lightwave Technol. 22, 520–525 (2004).

    Article  ADS  Google Scholar 

  37. Melloni, A. & Martinelli, M. Synthesis of direct-coupled-resonators bandpass filters for WDM systems. J. Lightwave Technol. 20, 296–303 (2002).

    Article  ADS  Google Scholar 

  38. Stefanou, N. & Modinos, A. Impurity bands in photonic insulators. Phys. Rev. B 57, 12127–12133 (1998).

    Article  ADS  Google Scholar 

  39. Little, B. E. & Chu, S. T. Theory of polarization rotation and conversion in vertically coupled microresonators. IEEE Photon. Technol. Lett. 12, 401–403 (2000).

    Article  ADS  Google Scholar 

  40. Morichetti, F., Melloni, A. & Martinelli, M. Effects of polarization rotation in optical ring-resonator-based devices. J. Lightwave Technol. 24, 573–585 (2006).

    Article  ADS  Google Scholar 

  41. Heebner, J. E., Chak, P., Pereira, S., Sipe, J. E. & Boyd, R. W. Distributed and localized feedback microresonator sequences for linear and nonlinear optics. J. Opt. Soc. Am. B 21, 1818–1832 (2004).

    Article  ADS  Google Scholar 

  42. Popovic, M. A., Manolatou, C. & Haus, H. A. Coupling-induced resonance frequency shifts in coupled dielectric multi-cavity filters. Opt. Express 14, 1208–1222 (2006).

    Article  ADS  Google Scholar 

  43. Ye, Y. et al. Finite-size effect on one dimensional coupled resonator optical waveguides. Phys. Rev. E 69, 056604 (2004).

    Article  ADS  MathSciNet  Google Scholar 

  44. Madsen, C. & Zhao, J. Optical Filter Design and Analysis: A Signal Processing Approach, Ch. 5. (Wiley, New York, 1999).

  45. Stenner, M. D., Gauthier, D. J. & Neifeld, M. A. Fast causal information transmission in a medium with a slow group velocity. Phys. Rev. Lett. 94, 053902 (2005).

    Article  ADS  Google Scholar 

  46. Khurgin, J. B. Expanding the bandwidth of slow-light photonic devices based on coupled resonators. Opt. Lett. 30, 513–515 (2005).

    Article  ADS  Google Scholar 

  47. Agrawal, G. P. Fiber-Optic Communication Systems 3rd edn, Ch. 4 (Wiley, New York, 2001).

    Google Scholar 

  48. Dulkeith, E., Vlasov, Y. A., Chen, X., Panoiu, N. & Osgood, R. Self-phase-modulation in submicron silicon-on-insulator photonic wires. Opt. Express 14, 5524–5534 (2006).

    Article  ADS  Google Scholar 

  49. Espinola, R., Dadap, J., Osgood, R., McNab, S. J. & Vlasov, Y. A. C-band wavelength conversion in silicon photonic wire waveguides. Opt. Express 13, 4341–4349 (2005).

    Article  ADS  Google Scholar 

  50. Espinola, R., Dadap, J., Osgood, R., McNab, S. J. & Vlasov, Y. A. Raman amplification in ultrasmall silicon-on-insulator photonic wire waveguides. Opt. Express 12, 3713–3718 (2004).

    Article  ADS  Google Scholar 

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Acknowledgements

This work was partially supported by the DARPA Slow Light program. The authors are grateful to C. Schow, L. Schares and D. Kuchta for help with BER and eye-diagram measurements, to S. McNab, B. Banke and J. Robert for AFM and LER measurements, and to W. Green for useful discussions.

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  1. IBM Thomas J. Watson Research Centre, Yorktown Heights, New York, 10598, USA

    Fengnian Xia, Lidija Sekaric & Yurii Vlasov

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Correspondence to Yurii Vlasov.

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Xia, F., Sekaric, L. & Vlasov, Y. Ultracompact optical buffers on a silicon chip. Nature Photon 1, 65–71 (2007). https://doi.org/10.1038/nphoton.2006.42

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