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Journal of the Optical Society of America A

Journal of the Optical Society of America A


  • Editor: Stephen A. Burns
  • Vol. 25, Iss. 10 — Oct. 1, 2008
  • pp: 2558–2570

Characterization of near-stoichiometric Ti : Li Nb O 3 strip waveguides with varied substrate refractive index in the guiding layer

De-Long Zhang, Pei Zhang, Hao-Jiang Zhou, and Edwin Yue-Bun Pun  »View Author Affiliations

JOSA A, Vol. 25, Issue 10, pp. 2558-2570 (2008)

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We have demonstrated the possibility that near-stoichiometric Ti : Li Nb O 3 strip waveguides are fabricated by carrying out vapor transport equilibration at 1060 ° C for 12 h on a congruent Li Nb O 3 substrate with photolithographically patterned 4 8 μ m wide, 115 nm thick Ti strips. Optical characterizations show that these waveguides are single mode at 1.5 μ m and show a waveguide loss of 1.3 dB cm for TM mode and 1.1 dB cm for TE mode. In the width/depth direction of the waveguide, the mode field follows the Gauss/Hermite–Gauss function. Secondary-ion-mass spectrometry (SIMS) was used to study Ti-concentration profiles in the depth direction and on the surface of the 6 μ m wide waveguide. The result shows that the Ti profile follows a sum of two error functions along the width direction and a complementary error function in the depth direction. The surface Ti concentration, 1 e width and depth, and mean diffusivities along the width and depth directions of the guide are similar to 3.0 × 10 21 cm 3 , 3.8 μ m , 2.6 μ m , 0.30 and 0.14 μ m 2 h , respectively. Micro-Raman analysis was carried out on the waveguide endface to characterize the depth profile of Li composition in the guiding layer. The results show that the depth profile of Li composition also follows a complementary error function with a 1 e depth of 3.64 μ m . The mean ( [ Li Li ] + [ Ti Li ] ) ( [ Nb Nb ] + [ Ti Nb ] ) ratio in the waveguide layer is about 0.98. The inhomogeneous Li-composition profile results in a varied substrate index in the guiding layer. A two-dimensional refractive index profile model in the waveguide is proposed by taking into consideration the varied substrate index and assuming linearity between Ti-induced index change and Ti concentration. The net waveguide surface index increments at 1545 nm are 0.0114 and 0.0212 for ordinary and extraordinary rays, respectively. Based upon the constructed index model, the fundamental mode field profile was calculated using the beam propagation method, and the mode sizes and effective index versus the Ti-strip width were calculated for three lower TM and TE modes using the variational method. An agreement between theory and experiment is obtained.

© 2008 Optical Society of America

OCIS Codes
(130.2790) Integrated optics : Guided waves
(130.3730) Integrated optics : Lithium niobate
(230.7380) Optical devices : Waveguides, channeled

ToC Category:
Integrated Optics

Original Manuscript: January 24, 2008
Revised Manuscript: July 29, 2008
Manuscript Accepted: August 12, 2008
Published: September 23, 2008

De-Long Zhang, Pei Zhang, Hao-Jiang Zhou, and Edwin Yue-Bun Pun, "Characterization of near-stoichiometric Ti:LiNbO3 strip waveguides with varied substrate refractive index in the guiding layer," J. Opt. Soc. Am. A 25, 2558-2570 (2008)

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  1. U. Schlarb and K. Betzler, “Refractive indices of lithium niobate as a function of temperature, wavelength, and composition: a generalized fit,” Phys. Rev. B 48, 15613-15620 (1993). [CrossRef]
  2. D. H. Jundt, M. M. Fejer, and R. L. Byer, “Optical properties of lithium-rich niobate fabricated by vapor transport equilibration,” IEEE J. Quantum Electron. 26, 135-138 (1990). [CrossRef]
  3. T. Fujiwara, M. Takahashi, M. Ohama, A. J. Ikushima, Y. Furukawa, and K. Kitamura, “Comparison of electro-optic effect between stoichiometric and congruent LiNbO3,” Electron. Lett. 35, 499-501 (1999). [CrossRef]
  4. T. Fujiwara, A. J. Ikushima, Y. Furukawa, and K. Kitamura, “Second-order nonlinearity in stoichiometric LiNbO3 and LiTaO3,” in Technical Digest of Meeting on New Aspects of Nonlinear Optical Materials and Devices (IEEE, 1999), pp. 2-4.
  5. V. Gopalan, T. E. Mitchell, Y. Furukawa, and K. Kitamura, “The role of nonstoichiometry in 180 degrees domain switching of LiNbO3 crystals,” Appl. Phys. Lett. 72, 1981-1981 (1998). [CrossRef]
  6. A. Grisard, E. Lallier, K. Polgar, and A. Peter, “Low electric field periodic poling of thick stoichiometric lithium niobate,” Electron. Lett. 36, 1043-1044 (2000). [CrossRef]
  7. Á. Péter, K. Polgár, L. Kovács, and K. Lengyel, “Threshold concentration of MgO in near-stoichiometric LiNbO3 crystals,” J. Cryst. Growth 284, 149-155 (2005). [CrossRef]
  8. Y. Furukawa, K. Kitamura, S. Takekawa, A. Miyamoto, M. Terao, and N. Suda, “Photorefraction in LiNbO3 as a function of [Li]/[Nb] and MgO concentrations,” Appl. Phys. Lett. 77, 2494-2496 (2000). [CrossRef]
  9. F. Jermann, D. M. Simon, and E. Kratzig, “Photorefractive properties of congruent and stoichiometric lithium niobate at high light intensities,” J. Opt. Soc. Am. B 12, 2066-2070 (1995). [CrossRef]
  10. R. J. Holmes and D. M. Smyth, “Titanium diffusion into LiNbO3 as a function of stoichiometry,” J. Appl. Phys. 55, 3531-3535 (1984). [CrossRef]
  11. H. Nakajima, M. Yuki, T. Oka, H. Yamauchi, S. Kurimura, I. Sakaguchi, and K. Kitamura, “Ti-diffused waveguides fabricated on stoichiometric LiNbO3,” in Technical Digest on Meeting on Photonics in Switching (Institute of Electronic, Information, and Communication Engineers, 2002), pp. 242-244.
  12. A. Hellwig, H. Suche, R. Schor, and W. Sohler, “Titanium-indiffused waveguides in magnesium oxide doped stoichiometric lithium niobate (MgO:SLN),” in Proceedings of the 12th European Conference on Integrated Optics (ECIO'05) (European Optical Society, 2005), paper ThB2-5.
  13. R. Mohan Kumar, F. Yamamoto, J. Ichikawa, H. Ryoken, I. Sakaguchi, X. Liu, M. Nakamura, K. Terabe, S. Takekawa, H. Haneda, and K. Kitamura, “SIMS-depth profile and microstructure studies of Ti-diffused Mg-doped near-stoichiometric lithium niobate waveguide,” J. Cryst. Growth 287, 472-477 (2006). [CrossRef]
  14. D. L. Zhang, W. H. Wong, and E. Y. B. Pun, “Near-stoichiometric Ti:LiNbO3 waveguides fabricated using vapor transport equilibration and Ti co-diffusion,” Appl. Phys. Lett. 85, 3002-3004 (2004). [CrossRef]
  15. D. L. Zhang, G. G. Siu, and E. Y. B. Pun, “Raman scattering and x-ray diffraction study of near-stoichiometric Ti:LiNbO3 waveguides,” Phys. Status Solidi A 202, 2521-2530 (2005). [CrossRef]
  16. M. Nakamura, S. Takekawa, S. Kurimura, K. Kitamura, and H. Nakajima, “Crystal growth and characterization of titanium-doped near-stoichiometric LiNbO3,” J. Cryst. Growth 264, 339-345 (2004). [CrossRef]
  17. G. I. Malovichko, V. G. Grachev, E. P. Kokanyan, O. F. Schirmer, K. Betzler, B. Gather, F. Jermann, S. Klauer, U. Schlarb, and M. Wohlecke, “Characterization of stoichiometric LiNbO3 grown from melts containing K2O,” Appl. Phys. A 56, 103-108 (1993). [CrossRef]
  18. M. Dinand and W. Sohler, “Theoretical modelling of optical amplification in Er-doped Ti:LiNbO3 waveguides,” IEEE J. Quantum Electron. 30, 1267-1276 (1994). [CrossRef]
  19. I. Baumann, R. Brinkmann, M. Dinand, W. Sohler, and S. Westenhöfer, “Ti:Er:LiNbO3 waveguide laser of optimized efficiency,” IEEE J. Quantum Electron. 32, 1695-1706 (1996). [CrossRef]
  20. M. Fukuma and J. Noda, “Optical properties of titanium-diffused LiNbO3 strip waveguides and their coupling-to-a-fiber characteristics,” Appl. Opt. 19, 591-597 (1980). [CrossRef] [PubMed]
  21. S. Fouchet, A. Carenco, C. Daguet, R. Guglielmi, and L. Riviere, “Wavelength dispersion of Ti induced refractive index change in LiNbO3 as a function of diffusion parameters,” J. Lightwave Technol. 5, 700-708 (1987). [CrossRef]
  22. E. Zolotoyabko, Y. Avrahami, W. Sauer, T. H. Metzger, and J. Peisl, “High-temperature phase transformation in Ti-diffused waveguide layers of LiNbO3,” Appl. Phys. Lett. 73, 1352-1354 (1998). [CrossRef]
  23. J. Crank, The Mathematics of Diffusion (Oxford U. Press, 1975), pp. 175-176.
  24. K. Sugii, K. Fukuma, and H. Iwasaki, “A study of titanium diffusion into LiNbO3 waveguides by electron probe analysis and x-ray diffraction methods,” J. Mater. Sci. 13, 523-533 (1978). [CrossRef]
  25. M. N. Armenise, C. Canali, M. De Sario, A. Carnera, P. Mazzoldi, and G. Celloti, “Characterization of (Ti0.65Nb0.35)O2 compound as a source for Ti-diffusion during Ti:LiNbO3 optical waveguide fabrication,” J. Appl. Phys. 54, 62-70 (1983). [CrossRef]
  26. C. E. Rice and R. J. Holmes, “A new rutile structure solid-solution phase in the LiNb3O8-TiO2 system, and its role in Ti diffusion into LiNbO3,” J. Appl. Phys. 60, 3836-3839 (1986). [CrossRef]
  27. H. F. da Silva, J. M. Filho, S. C. Zilio, and F. D. Nunes, “Modelling Ti in-diffusion in LiNbO3,” J. Phys. Condens. Matter 9, 357-364 (1997). [CrossRef]
  28. D. H. Jundt, M. M. Fejer, R. G. Norwood, and P. F. Bordui, “Composition dependence of lithium diffusivity in lithium niobate at high temperature,” J. Appl. Phys. 72, 3468-3473 (1992). [CrossRef]
  29. F. Caccavale, P. Chakraborty, A. Quaranta, I. Mansour, G. Gianello, S. Bosso, R. Corsini, and G. Mussi, “Secondary-ion-mass spectrometry and near-field studies of Ti:LiNbO3 optical waveguides,” J. Appl. Phys. 78, 5345-5350 (1995). [CrossRef]
  30. F. Caccavale, A. Morbiato, M. Natali, C. Sada, and F. Segato, “Correlation between optical and compositional properties of Ti:LiNbO3 channel optical waveguides,” J. Appl. Phys. 87, 1007-1011 (2000). [CrossRef]
  31. F. Caccavale, C. Sada, F. Segato, and F. Cavuoti, “Secondary ion mass spectrometry and optical characterization of Ti:LiNbO3 optical waveguides,” Appl. Surf. Sci. 150, 195-201 (1999). [CrossRef]

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