OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 17 — Aug. 15, 2011
  • pp: 15739–15749

Air-gap structure between integrated LiNbO3 optical modulators and micromachined Si substrates

Ryo Takigawa, Eiji Higurashi, Tadatomo Suga, and Tetsuya Kawanishi  »View Author Affiliations

Optics Express, Vol. 19, Issue 17, pp. 15739-15749 (2011)

View Full Text Article

Enhanced HTML    Acrobat PDF (1178 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



The air-gap structure between integrated LiNbO3 optical modulators and micromachined Si substrates is reported for high-speed optoelectronic systems. The calculated and experimental results show that the high permittivity of the Si substrate decreases the resonant modulation frequency to 10 GHz LiNbO3 resonant-type optical modulator chips on the Si substrate. To prevent this substrate effect, an air-gap was formed between the LiNbO3 modulator and the Si substrate. The ability to fabricate the air-gap structure was demonstrated using low-temperature flip-chip bonding (100 °C) and a Si micromachining process, and its performance was experimentally verified.

© 2011 OSA

OCIS Codes
(130.3120) Integrated optics : Integrated optics devices
(130.3730) Integrated optics : Lithium niobate
(130.4110) Integrated optics : Modulators

ToC Category:
Integrated Optics

Original Manuscript: April 20, 2011
Revised Manuscript: June 23, 2011
Manuscript Accepted: June 24, 2011
Published: August 2, 2011

Ryo Takigawa, Eiji Higurashi, Tadatomo Suga, and Tetsuya Kawanishi, "Air-gap structure between integrated LiNbO3 optical modulators and micromachined Si substrates," Opt. Express 19, 15739-15749 (2011)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. A. 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(6975), 615–618 (2004). [CrossRef] [PubMed]
  2. Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005). [CrossRef] [PubMed]
  3. Q. Xu, S. Manipatruni, B. Schmidt, J. Shakya, and M. Lipson, “12.5 Gbit/s carrier-injection-based silicon micro-ring silicon modulators,” Opt. Express 15(2), 430–436 (2007). [CrossRef] [PubMed]
  4. W. M. J. Green, M. J. Rooks, L. Sekaric, and Y. A. Vlasov, “Ultra-compact, low RF power, 10 Gb/s silicon Mach-Zehnder modulator,” Opt. Express 15(25), 17106–17113 (2007). [CrossRef] [PubMed]
  5. S. Manipatruni, L. Chen, and M. Lipson, “Ultra high bandwidth WDM using silicon microring modulators,” Opt. Express 18(16), 16858–16867 (2010). [CrossRef] [PubMed]
  6. E. L. Friedrich, M. G. Oberg, B. Broberg, S. Nilsson, and S. Valette, “Hybrid integration of Semiconductor Lasers with Si-based single-mode ridge waveguides,” J. Lightwave Technol. 10(3), 336–340 (1992). [CrossRef]
  7. T. Hashimoto, Y. Nakasuga, Y. Yamada, H. Terui, M. Yanagisawa, Y. Akahori, Y. Tohmori, K. Kato, and Y. Suzuki, “Multichip optical hybrid integration technique with planar lightwave circuit platform,” J. Lightwave Technol. 16(7), 1249–1258 (1998). [CrossRef]
  8. R. Sawada, E. Higurashi, and Y. Jin, “Hybrid microlaser encoder,” J. Lightwave Technol. 21(3), 815–820 (2003). [CrossRef]
  9. E. Higurashi, R. Sawada, and T. Ito, “An integrated laser blood flowmeter,” J. Lightwave Technol. 21(3), 591–595 (2003). [CrossRef]
  10. E. Higurashi and R. Sawada, “Micro-encoder based on higher-order diffracted light interference,” J. Micromech. Microeng. 15(8), 1459–1465 (2005). [CrossRef]
  11. H. L. Hsiao, H. C. Lan, C. C. Chang, C. Y. Lee, S. P. Chen, C. H. Hsu, S. F. Chang, Y. S. Lin, F. M. Kuo, J. W. Shi, and M. L. Wu, “Compact and passive-alignment 4-channel × 25-Gbps optical interconnect modules based on silicon optical benches with 45° micro-reflectors,” Opt. Express 17(26), 24250–24260 (2009). [CrossRef] [PubMed]
  12. K. Ohira, K. Kobayashi, N. Iizuka, H. Yoshida, M. Ezaki, H. Uemura, A. Kojima, K. Nakamura, H. Furuyama, and H. Shibata, “On-chip optical interconnection by using integrated III-V laser diode and photodetector with silicon waveguide,” Opt. Express 18(15), 15440–15447 (2010). [CrossRef] [PubMed]
  13. H. Takagi, R. Maeda, and T. Suga, “Room-temperature wafer bonding of Si to LiNbO3, LiTaO3 and Gd3Ga5O12 by Ar-beam surface activation,” J. Micromech. Microeng. 11(4), 348–352 (2001). [CrossRef]
  14. R. Takigawa, E. Higurashi, T. Suga, S. Shinada, and T. Kawanishi, “Low-temperature Au-to-Au bonding for LiNbO3/Si structure achieved in ambient,” IEICE Trans. Electron. E E90(C), 145–146 (2007). [CrossRef]
  15. E. Higurashi, T. Imamura, T. Suga, and R. Sawada, “Low-temperature bonding of laser diode chips on silicon substrates using plasma activation of Au films,” IEEE Photon. Technol. Lett. 19(24), 1994–1996 (2007). [CrossRef]
  16. R. Takigawa, E. Higurashi, T. Suga, and R. Sawada, “Room-temperature bonding of vertical cavity surface emission laser diode chips on silicon substrates using Au microbumps,” Appl. Phys. Express 1(24), 112201 (2008). [CrossRef]
  17. E. Higurashi, D. Chino, T. Suga, and R. Sawada, “Au-Au surface-activated bonding and its application to optical microsensors with three dimensional structure,” IEEE J. Sel. Top. Quantum Electron. 15(5), 1500–1505 (2009). [CrossRef]
  18. R. Takigawa, E. Higurashi, T. Suga, and T. Kawanishi, “Passive alignment and mounting of LiNbO3 waveguide chips on Si substrates by low-temperature solid-state bonding of Au,” IEEE J. Sel. Top. Quantum Electron. 17(3), 652–658 (2011). [CrossRef]
  19. E. Higurashi, R. Sawada, and T. Suga, “Optical microsensors integration technologies for biomedical applications,” IEICE Trans. Electron. E E92(C), 231–238 (2009). [CrossRef]
  20. T. Suga, T. Itoh, Z. Xu, M. Tomita, and A. Yamauchi, “Surface activated bonding for new flip chip and bumpless interconnect systems,” in Proc. 52nd Electron. Components Technol. Conf. San Diego CA 105–111, 2002.
  21. T. Kawanishi, S. Oikawa, K. Higuma, Y. Matsuo, and M. Izutsu, “LiNbO3 resonant-type optical modulator with double-stub structure,” Electron. Lett. 37(20), 1244–1246 (2001). [CrossRef]
  22. S. Oikawa, T. Kawanishi, K. Higuma, Y. Matsuo, and M. Izutsu, “Double-stub structure for resonant-type optical modulators using 20 –thick electrode,” IEEE Photon. Technol. Lett. 15(2), 221–223 (2003). [CrossRef]
  23. Test Methods and Procedures For Microelectronics, “MIL-STD-883E,” Method 2027, 2 (1989).
  24. E. J. Murphy, T. C. Rice, L. Mccaughan, G. T. Harvey, and P. H. Read, “Permanent attachment of single-mode fiber arrays to waveguides,” J. Lightwave Technol. 3(4), 795–799 (1985). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited