Near-stoichiometric Ti : LiNbO3 strip waveguide with varied substrate refractive index in waveguide layer

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Original languageEnglish
Article number24214
Journal / PublicationChinese Physics B
Issue number2
Publication statusPublished - 2010


We report the near-stoichiometric Ti:LiNbO3 strip waveguides fabricated by vapour transport equilibration (VTE) at 1060 °C for 12 h and co-diffusion of 4-8 μm wide, 115-nm thick Ti-strips. Optical studies show that these waveguides are monomode at 1.5 μm and have losses of 1.3 and 1.1 dB/cm for the TM and TE modes, respectively. In the waveguide width/depth direction, the mode field follows a Gauss/Hermite-Gauss profile. A secondary ion mass spectrometry study reveals that the Ti profile follows a sum of two error functions along the width direction and a complementary error function in the depth direction. Micro-Raman analysis shows that the Li-composition in the depth direction also follows a complementary error function. The mean Li/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, and the refractive index profile in the guiding layer is given. © 2010 Chinese Physical Society and IOP Publishing Ltd.

Research Area(s)

  • 2D refractive index profile, Licomposition profile, Near-stoichiometric Ti:LiNbO3 strip waveguide, Varied substrate refractive index