KTiOPO4 was implanted by 2.0 MeV and 2.8 MeV He ions with the same dos
e of 1.5 x 10(16) ions cm(-2) to form double barrier waveguides. The d
ark modes were measured by prism coupling. We have used the method of
Pluck et al. to fit the refractive index profile of double barrier wav
eguides in KTiOPO4. The close agreement between the measured and calcu
lated mode indices indicates that the refractive index profile obtaine
d for double barrier waveguides in KTiOPO4 seems to be reasonable. (C)
1998 Published by Elsevier Science Ltd.