Complete optical isolation created by indirect interband photonic transitions

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  • A Corrigendum to this article was published on 15 April 2009


Achieving on-chip optical signal isolation is a fundamental difficulty in integrated photonics1. The need to overcome this difficulty is becoming increasingly urgent, especially with the emergence of silicon nano-photonics2,3,4, which promises to create on-chip optical systems at an unprecedented scale of integration. Until now, there have been no techniques that provide complete on-chip signal isolation using materials or processes that are fundamentally compatible with silicon CMOS processes. Based on the effects of photonic transitions5,6, we show here that a linear, broadband and non-reciprocal isolation can be accomplished by spatial–temporal refractive index modulations that simultaneously impart frequency and wavevector shifts during the photonic transition process. We further show that a non-reciprocal effect can be accomplished in dynamically modulated micrometre-scale ring-resonator structures. This work demonstrates that on-chip isolation can be accomplished with dynamic photonic structures in standard material systems that are widely used for integrated optoelectronic applications.

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Figure 1: Schematic of indirect photonic transition in a silicon slab waveguide.
Figure 2: Non-reciprocal frequency conversion in a waveguide.
Figure 3: Schematic of a ring resonator designed for non-reciprocal frequency conversion.
Figure 4: Field distribution and frequency response of the modulated coupled ring–waveguide structure.

Change history

  • 15 April 2009

    In the version of this Letter originally published, equation (4) was incorrect, as was the final sentence in the third paragraph from the end of page 92. These errors have now been corrected in the HTML and PDF versions.


  1. 1

    Soljacic, M. & Joannopoulos, J. D. Enhancement of nonlinear effects using photonic crystals. Nature Mater. 3, 211–219 (2004).

  2. 2

    Pavesi, L. & Lockwood, D. J. Silicon Photonics (Springer, 2004).

  3. 3

    Almeida, V. R., Barrios, C. A., Panepucci, R. R. & Lipson, M. All-optical control of light on a silicon chip. Nature 431, 1081–1084 (2004).

  4. 4

    Miller, D. A. B. Optical interconnects to silicon. IEEE J. Sel. Top. Quant. Electron. 6, 1312–1317 (2000).

  5. 5

    Winn, J. N., Fan, S., Joannopoulos, J. D. & Ippen, E. P. Interband transitions in photonic crystals. Phys. Rev. B 59, 1551–1554 (1998).

  6. 6

    Dong, P., Preble, S. F., Robinson, J. T., Manipatruni, S. & Lipson, M. Inducing photonic transitions between discrete modes in a silicon optical microcavity. Phys. Rev. Lett. 100, 033904 (2008).

  7. 7

    Espinola, R. L., Izuhara, T., Tsai, M. C., Osgood, R. M. Jr & Dötsch, H. Magneto-optical nonreciprocal phase shift in garnet/silicon-on-insulator waveguides. Opt. Lett. 29, 941–943 (2004).

  8. 8

    Levy, M. A nanomagnetic route to bias-magnet-free, on-chip Faraday rotators. J. Opt. Soc. Am. B 22, 254–260 (2005).

  9. 9

    Zaman, T. R., Guo, X. & Ram, R. J. Faraday rotation in an InP waveguide. Appl. Phys. Lett. 90, 023514 (2007).

  10. 10

    Dötsch, H. et al. Applications of magneto-optical waveguides in integrated optics: review. J. Opt. Soc. Am. B 22, 240–253 (2005).

  11. 11

    Soljaic, M., Luo, C., Joannopoulos, J. D. & Fan, S. Nonlinear photonic microdevices for optical integration. Opt. Lett. 28, 637–639 (2003).

  12. 12

    Gallo, K., Assanto, G., Parameswaran, K. R. & Fejer, M. M. All-optical diode in a periodically poled lithium niobate waveguide. Appl. Phys. Lett. 79, 314–316 (2001).

  13. 13

    Ibrahim, S. K., Bhandare, S., Sandel, D., Zhang, H. & Noe, R. Non-magnetic 30 dB integrated optical isolator in III/V material. Electron. Lett. 40, 1293–1294 (2004).

  14. 14

    Yariv, A. Electro-optic frequency modulation in optical resonators. Proc. IEEE 52, 719–720 (1964).

  15. 15

    Siegman, A. Lasers 986 (University Science Books, 1986).

  16. 16

    Reed, E. J., Soljacic, M. & Joannopoulos, J. D. Reversed Doppler effect in photonic crystals. Phys. Rev. Lett. 91, 133901 (2003).

  17. 17

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

  18. 18

    Notomi, M. & Mitsugi, S. Wavelength conversion via dynamic refractive index tuning of a cavity. Phys. Rev. A 73, 051803(R) (2006).

  19. 19

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

  20. 20

    Preble, S. F., Xu, Q. & Lipson, M. Changing the colour of light in a silicon resonator. Nature Photon. 1, 293–296 (2007).

  21. 21

    Jiao, Y., Fan, S. & Miller, D. A. B. Demonstrations of systematic photonic crystal design and optimization by low rank adjustment: an extremely compact mode separator. Opt. Lett. 30, 141–143 (2005).

  22. 22

    Lee, B. T. & Shin, S. Y. Mode-order converter in a multimode waveguide. Opt. Lett. 28, 1660–1662 (2003).

  23. 23

    Fan, S. et al. Guided and defect modes in periodic dielectric waveguides. J. Opt. Soc. Am. B 12, 1267–1272 (1995).

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This work was supported in part by the National Science Foundation (grant no. ECS-0622212). S.F. acknowledges discussions with Z. Wang and M. Soljacic. The computations were performed at the Pittsburgh Supercomputing Center and the National Center for Supercomputing Applications, through the support of the National Science Foundation TeraGrid programme.

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Correspondence to Shanhui Fan.

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