Abstract

We describe a class of modulator design involving slot waveguides and electro-optic polymer claddings. Such geometries enable massive enhancement of index tuning when compared to more conventional geometries. We present a semi-analytic method of predicting the index tuning achievable for a given geometry and electro-optic material. Based on these studies, as well as previous experimental results, we show designs for slot waveguide modulators that, when realized in a Mach-Zehnder configuration, will allow for modulation voltages that are orders of magnitude lower than the state of the art. We also discuss experimental results for nano-slot waveguides.

© 2007 Optical Society of America

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References

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  1. N. Bloembergen, P. S. Pershan and L. R. Wilcox, "Microwave modulation of light in paramagnetic crystals," Phys. Rev. 120, 2014-2023 (1960).
    [CrossRef]
  2. Y. Yamabayashi and M. Nakazawa, "Terabit transmission technology," NTT.Rev. 11, 23-32 (1999).
  3. Y. Q. Shi, C. Zhang, H. Zhang, J. H. Bechtel, L. R. Dalton, B. H. Robinson and W. H. Steier, "Low (sub-1-volt) halfwave voltage polymeric electro-optic modulators achieved by controlling chromophore shape," Science 288, 119-122 (2000).
    [CrossRef]
  4. O. Mitomi, K. Noguchi and H. Miyazawa, "Broadband and low driving-voltage LiNbO3 optical modulators," IEEE Proc. Optoelectron. 135, 360-364 (1998).
    [CrossRef]
  5. D. Rutledge, "Filters," in The Electronics of Radio (Cambridge University Press, Cambridge, 1999).
  6. M. M. de Lima, M. Beck, R. Hey and P. V. Santos, "Compact Mach-Zehnder acousto-optic modulator," Appl. Phys. Lett. 89, 3 (2006).
    [CrossRef]
  7. E. L. Wooten, K. M. Kissa, A. Yi-Yan, E. J. Murphy, D. A. Lafaw, P. F. Hallameier, D. Maack, D. V. Attanasio, D. J. Fritz, G. J. McBrien, D. E. Bossi, "A review of lithium niobate modulators for fiber-optic communications systems," IEEE J. Sel. Top. Quantum Electron. 6, 69-82 (2000).
    [CrossRef]
  8. M. Lipson, "Guiding, modulating, and emitting light on silicon - Challenges and opportunities," J. Lightwave Technol. 23, 4222-4238 (2005).
    [CrossRef]
  9. H. Fukano, T. Yamanaka, M. Tamura and Y. Kondo, "Very-low-driving-voltage electroabsorption modulators operating at 40 Gb/s," J. Lightwave Technol. 24, 2219-2224 (2006).
    [CrossRef]
  10. M. T. Tinker and J. B. Lee, "Thermal and optical simulation of a photonic crystal light modulator based on the thermo-optic shift of the cut-off frequency," Opt. Express 13, 7174-7188 (2005).
    [CrossRef] [PubMed]
  11. Y. Enami, C. T. Derose, D. Mathine, C. Loychik, C. Greenlee, R. A. Norwood, R. D. Kim, J. Luo, Y. Tian, A. K. Y. Jen and N. Peyghambarian, "Hybrid polymer/sol-gel waveguide modulators with exceptionally large electro-optic coefficients," Nature Photon. 6, 180-185 (2007).
    [CrossRef]
  12. A. S. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu and M. Paniccia, "A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor," Nature 427, 615-618 (2004).
    [CrossRef] [PubMed]
  13. J. J. Whelehan, "Low-noise amplifiers- then and now," IEEE Trans. on Microwave Theory Techniques 50, 806-813 (2002).
    [CrossRef]
  14. H. Tazawa, Y. Kuo, I. Dunayevskiy, J. Luo, A. K. Y. Jen, H. Fetterman and W. Steier, "Ring resonator based electrooptic polymer traveling-wave modulator," IEEE J. Lightwave Technol. 24, 3514-3519 (2006).
    [CrossRef]
  15. V. R. Almeida, Q. F. Xu, C. A. Barrios and M. Lipson, "Guiding and confining light in void nanostructure," Opt. Letters 29, 1209-1211 (2004).
    [CrossRef]
  16. T. Baehr-Jones, M. Hochberg, G. X. Wang, R. Lawson, Y. Liao, P. A. Sullivan, L. Dalton, A. K. Y. Jen, A. Scherer, "Optical modulation and detection in slotted Silicon waveguides," Opt. Express 13, 5216-5226 (2005).
    [CrossRef] [PubMed]
  17. Professor LarryR.  Dalton, Chemistry Department, University of Washington, Box 351700, Seattle, WA, 98195 (personal communication 2006).
  18. T. Baehr-Jones, M. Hochberg, C. Walker and A. Scherer, "High-Q ring resonators in thin silicon-on-insulator," Appl. Phys. Lett. 85, 3346-3347 (2004).
    [CrossRef]
  19. A. Yariv, "The Modulation of Optical Radiation," in Quantum Electronics (John Wiley and Sons, New York, 1989).
  20. T. Baehr-Jones, M. Hochberg, C. Walker, E. Chan, D. Koshinz, W. Krug and A. Scherer, "Analysis of the tuning sensitivity of silicon-on-insulator optical ring resonators," IEEE J. Lightwave Technol. 23, 4215-4221 (2005).
    [CrossRef]
  21. M. Hochberg, T. Baehr-Jones, C. Walker, J. Witzens, L. C. Gunn and A. Scherer, "Segmented waveguides in thin silicon-on-insulator," J. Opt. Soc. Am. B 22, 1493-1497 (2005).
    [CrossRef]
  22. G. Wang, M. Hochberg, and T. Baehr-Jones are preparing a manuscript to be called "Design and Fabrication of Segmented, Slotted Waveguides for Electro-Optic Modulation."
  23. T. Baehr-Jones, M. Hochberg, C. Walker, and A. Scherer, "High-Q optical resonators in silicon-on-insulator-based slot waveguides," Appl. Phys. Lett. 86, 81101-81104 (2005).
    [CrossRef]

2007 (1)

Y. Enami, C. T. Derose, D. Mathine, C. Loychik, C. Greenlee, R. A. Norwood, R. D. Kim, J. Luo, Y. Tian, A. K. Y. Jen and N. Peyghambarian, "Hybrid polymer/sol-gel waveguide modulators with exceptionally large electro-optic coefficients," Nature Photon. 6, 180-185 (2007).
[CrossRef]

2006 (3)

H. Tazawa, Y. Kuo, I. Dunayevskiy, J. Luo, A. K. Y. Jen, H. Fetterman and W. Steier, "Ring resonator based electrooptic polymer traveling-wave modulator," IEEE J. Lightwave Technol. 24, 3514-3519 (2006).
[CrossRef]

M. M. de Lima, M. Beck, R. Hey and P. V. Santos, "Compact Mach-Zehnder acousto-optic modulator," Appl. Phys. Lett. 89, 3 (2006).
[CrossRef]

H. Fukano, T. Yamanaka, M. Tamura and Y. Kondo, "Very-low-driving-voltage electroabsorption modulators operating at 40 Gb/s," J. Lightwave Technol. 24, 2219-2224 (2006).
[CrossRef]

2005 (6)

2004 (3)

T. Baehr-Jones, M. Hochberg, C. Walker and A. Scherer, "High-Q ring resonators in thin silicon-on-insulator," Appl. Phys. Lett. 85, 3346-3347 (2004).
[CrossRef]

V. R. Almeida, Q. F. Xu, C. A. Barrios and M. Lipson, "Guiding and confining light in void nanostructure," Opt. Letters 29, 1209-1211 (2004).
[CrossRef]

A. S. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu and M. Paniccia, "A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor," Nature 427, 615-618 (2004).
[CrossRef] [PubMed]

2002 (1)

J. J. Whelehan, "Low-noise amplifiers- then and now," IEEE Trans. on Microwave Theory Techniques 50, 806-813 (2002).
[CrossRef]

2000 (2)

E. L. Wooten, K. M. Kissa, A. Yi-Yan, E. J. Murphy, D. A. Lafaw, P. F. Hallameier, D. Maack, D. V. Attanasio, D. J. Fritz, G. J. McBrien, D. E. Bossi, "A review of lithium niobate modulators for fiber-optic communications systems," IEEE J. Sel. Top. Quantum Electron. 6, 69-82 (2000).
[CrossRef]

Y. Q. Shi, C. Zhang, H. Zhang, J. H. Bechtel, L. R. Dalton, B. H. Robinson and W. H. Steier, "Low (sub-1-volt) halfwave voltage polymeric electro-optic modulators achieved by controlling chromophore shape," Science 288, 119-122 (2000).
[CrossRef]

1999 (1)

Y. Yamabayashi and M. Nakazawa, "Terabit transmission technology," NTT.Rev. 11, 23-32 (1999).

1998 (1)

O. Mitomi, K. Noguchi and H. Miyazawa, "Broadband and low driving-voltage LiNbO3 optical modulators," IEEE Proc. Optoelectron. 135, 360-364 (1998).
[CrossRef]

1960 (1)

N. Bloembergen, P. S. Pershan and L. R. Wilcox, "Microwave modulation of light in paramagnetic crystals," Phys. Rev. 120, 2014-2023 (1960).
[CrossRef]

Appl. Phys. Lett. (3)

M. M. de Lima, M. Beck, R. Hey and P. V. Santos, "Compact Mach-Zehnder acousto-optic modulator," Appl. Phys. Lett. 89, 3 (2006).
[CrossRef]

T. Baehr-Jones, M. Hochberg, C. Walker and A. Scherer, "High-Q ring resonators in thin silicon-on-insulator," Appl. Phys. Lett. 85, 3346-3347 (2004).
[CrossRef]

T. Baehr-Jones, M. Hochberg, C. Walker, and A. Scherer, "High-Q optical resonators in silicon-on-insulator-based slot waveguides," Appl. Phys. Lett. 86, 81101-81104 (2005).
[CrossRef]

IEEE J. Lightwave Technol. (2)

T. Baehr-Jones, M. Hochberg, C. Walker, E. Chan, D. Koshinz, W. Krug and A. Scherer, "Analysis of the tuning sensitivity of silicon-on-insulator optical ring resonators," IEEE J. Lightwave Technol. 23, 4215-4221 (2005).
[CrossRef]

H. Tazawa, Y. Kuo, I. Dunayevskiy, J. Luo, A. K. Y. Jen, H. Fetterman and W. Steier, "Ring resonator based electrooptic polymer traveling-wave modulator," IEEE J. Lightwave Technol. 24, 3514-3519 (2006).
[CrossRef]

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

E. L. Wooten, K. M. Kissa, A. Yi-Yan, E. J. Murphy, D. A. Lafaw, P. F. Hallameier, D. Maack, D. V. Attanasio, D. J. Fritz, G. J. McBrien, D. E. Bossi, "A review of lithium niobate modulators for fiber-optic communications systems," IEEE J. Sel. Top. Quantum Electron. 6, 69-82 (2000).
[CrossRef]

IEEE Proc. Optoelectron. (1)

O. Mitomi, K. Noguchi and H. Miyazawa, "Broadband and low driving-voltage LiNbO3 optical modulators," IEEE Proc. Optoelectron. 135, 360-364 (1998).
[CrossRef]

IEEE Trans. on Microwave Theory Techniques (1)

J. J. Whelehan, "Low-noise amplifiers- then and now," IEEE Trans. on Microwave Theory Techniques 50, 806-813 (2002).
[CrossRef]

J. Lightwave Technol. (2)

J. Opt. Soc. Am. B (1)

Nature (1)

A. S. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu and M. Paniccia, "A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor," Nature 427, 615-618 (2004).
[CrossRef] [PubMed]

Nature Photon. (1)

Y. Enami, C. T. Derose, D. Mathine, C. Loychik, C. Greenlee, R. A. Norwood, R. D. Kim, J. Luo, Y. Tian, A. K. Y. Jen and N. Peyghambarian, "Hybrid polymer/sol-gel waveguide modulators with exceptionally large electro-optic coefficients," Nature Photon. 6, 180-185 (2007).
[CrossRef]

Opt. Express (2)

Opt. Letters (1)

V. R. Almeida, Q. F. Xu, C. A. Barrios and M. Lipson, "Guiding and confining light in void nanostructure," Opt. Letters 29, 1209-1211 (2004).
[CrossRef]

Phys. Rev. (1)

N. Bloembergen, P. S. Pershan and L. R. Wilcox, "Microwave modulation of light in paramagnetic crystals," Phys. Rev. 120, 2014-2023 (1960).
[CrossRef]

Rev. (1)

Y. Yamabayashi and M. Nakazawa, "Terabit transmission technology," NTT.Rev. 11, 23-32 (1999).

Science (1)

Y. Q. Shi, C. Zhang, H. Zhang, J. H. Bechtel, L. R. Dalton, B. H. Robinson and W. H. Steier, "Low (sub-1-volt) halfwave voltage polymeric electro-optic modulators achieved by controlling chromophore shape," Science 288, 119-122 (2000).
[CrossRef]

Other (4)

D. Rutledge, "Filters," in The Electronics of Radio (Cambridge University Press, Cambridge, 1999).

Professor LarryR.  Dalton, Chemistry Department, University of Washington, Box 351700, Seattle, WA, 98195 (personal communication 2006).

A. Yariv, "The Modulation of Optical Radiation," in Quantum Electronics (John Wiley and Sons, New York, 1989).

G. Wang, M. Hochberg, and T. Baehr-Jones are preparing a manuscript to be called "Design and Fabrication of Segmented, Slotted Waveguides for Electro-Optic Modulation."

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Figures (4)

Fig. 1.
Fig. 1.

Panel A: Isometric three dimensional schematic of a conventional Mach-Zehnder polymer interferometer, showing top contact, waveguide, and bottom contact layers. Panel B: Top-down layout of a slot-waveguide based optical modulator. C: Three dimensional, isometric schematic of a slot-waveguide modulator, showing the slot waveguide, segmentation region and metal contacts. The device functions by maintaining the two arms of the slot waveguide at differing voltages, creating a strong electric field in the slot.

Fig. 2.
Fig. 2.

A plot of various susceptibilities as shown in table 1 for differing gap sizes. Making the gap smaller leads to substantial improvements in the figure of merit.

Fig. 3.
Fig. 3.

Panels A and B show a conventional electrode geometry for a nonlinear polymer waveguide with the configuration used by Tazawa et al. Panel A shows the optical mode with ∣E∣ plotted in increments of 10%, for a mode with propagating power of 1 Watt. Panel B shows a contour plot of the static electric field, with the field of view slightly enlarged. Panels C and D show analogous data for the most optimal slot waveguide geometry. In the slot waveguide, the Silicon provides both the optical guiding layer and the electrical contacts.

Fig. 4.
Fig. 4.

Panel A shows a transmission spectra of an electroded slot waveguide resonator with a gap of 70 nm. Fiber to fiber insertion loss is plotted in dB, against the test laser wavelength in nm. Panel B shows an SEM image of a portion of a typical slot waveguide with a sub-100 nm slot. The cursor width is 57 nm in this image.

Tables (1)

Tables Icon

Table 1 shows the results of a design study involving a number of different slot waveguide configurations. We show what figures of merit will be for waveguides involving wider and narrower slots, higher arms, and those with more than one slot.

Equations (8)

Equations on this page are rendered with MathJax. Learn more.

1 ( n + δn ) 2 1 n 2 = r 33 E dc
δε = E dc ( n 4 r 33 )
δ n eff = E dc E opt x 2 dA 2 Re ( Ex opt * H y opt Ey opt * H y opt ) dA 1 Z 0 ( n 4 r 33 )
γ = ( E dc V ) E opt x 2 dA 2 Re ( Ex opt * Hy opt Ey opt * H x opt ) dA 1 Z 0
n eff V = γ ( n 4 r 33 )
γ = 1 ( 2 ng )
V π L = π 2 k 0 ( n V )
f V = c λ n V ( n λ n λ )

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