Secondary-ion mass spectrometry was used to study Ti-concentration profiles in the depth direction and at the surface of near-stoichiometric Ti:LiNbO3 strip wave-guides fabricated using phase transport equilibration and co-diffusion of Ti-metal strips. The

results showed that the profile of the Ti concentration along the width direction on the wave guide surface could be fitted by a sum of 2 error functions. In the depth direction, the Ti concentration obeyed a complementary error function or a generalized Gaussian function. The surface Ti concentration, 1/e width and depth, and mean diffusivities in the width and depth directions of the guide were, 1.04 x 1021/cm3, 8.5µm, 6.3µm, 0.18 and 0.1µm2/h, respectively. The 2-dimensional refractive index profile in the near-stoichiometric wave-guides was constructed indirectly by assuming a linearity between the Ti-induced index change and the Ti concentration. The surface refractive index increments at 1545nm were evaluated to be 3.132 x 10-3 and 1.186 x 10-2.

Secondary-Ion Mass Spectrometry Study on Near-Stoichiometric LiNbO3 Strip Waveguide Fabricated by Vapour Transport Equilibration and Ti Co-Diffusion. D.L.Zhang, Z.Yang, W.H.Wong, E.Y.B.Pun: Philosophical Magazine, 2007, 87[1], 63-75

Table 132

Ionic Conductivity of N-Doped LiNbO3

(deposited under a constant Ar partial pressure of 0.0009Torr)

 

PN (Torr)

(S/cm)

E (eV)

0

6 x 10-9

0.69

4 x 10-4

7 x 10-9

0.65

5 x 10-4

2 x 10-8

0.62

6 x 10-4

1 x 10-7

0.55

7 x 10-4

2 x 10-7

0.53

8 x 10-4

5 x 10-7

0.51

9 x 10-4

3 x 10-7

0.50

1 x 10-3

9 x 10-8

0.52