Open AccessRefractive index profiling of an optical waveguide from the determination of the effective index with measured differential fields
Author(s) -
Wan-Shao Tsai,
San-Yu Ting,
PeiKuen Wei
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.026766
Subject(s) - lithium niobate , refractive index , optics , materials science , waveguide , planar , refractive index profile , optoelectronics , physics , computer graphics (images) , computer science
The evanescent tails of a guiding mode as well as its first and second derivatives were measured by a modified end-fire coupling method. The effective index of the waveguide can be obtained by simultaneously fitting these three fields using single parameter. Combined with an inverse calculation algorithm, the fields with fitted evanescent tails showed great improvement in the refractive index profiling of the optical waveguide, especially at the substrate region. Single-mode optical fibers and planar waveguides of proton-exchanged (PE) and titanium-indiffusion (Ti:LiNbO3) on lithium niobate substrates with different refractive index profiles were measured for the demonstration.