Test structures for characterization of electrooptic waveguide modulators in lithium niobate

Author

Wooten, Ed L. ; Chang, William S C

Author_Institution

Dept. of Electr. & Comput. Eng., California Univ., San Diego, La Jolla, CA, USA

Volume

29

Issue

1

fYear

1993

fDate

1/1/1993 12:00:00 AM

Firstpage

161

Lastpage

170

Abstract

A method of determining the critical parameters of waveguide modulators, using a set of test devices fabricated on a single chip, is presented. The five parameters are the depth and lateral Ti diffusion lengths, the peak index change in the waveguides, the electrooptic coefficient, and the buffer layer dielectric constant. The finite element method is used for calculation of optical modes in waveguides with graded refractive index profiles. The integral equation method is used for calculation of the static electric field due to electrodes in a three-layer structure of air, buffer layer, and LiNbO₃. The test set includes a planar waveguide, Mach-Zehnder modulators, symmetrically perturbed directional couplers, and widened X modulators. Several test chips have been fabricated using different fabrication conditions. The parameter values determined using this method are compared with those reported by other authors

Keywords

electro-optical devices; finite element analysis; gradient index optics; integrated optics; lithium compounds; optical modulation; optical testing; optical waveguides; optical workshop techniques; permittivity; titanium; LiNbO₃:Ti; Mach-Zehnder modulators; buffer layer dielectric constant; critical parameters; depth; electrodes; electrooptic coefficient; electrooptic waveguide modulators; fabrication conditions; finite element method; graded refractive index profiles; integral equation method; lateral Ti diffusion lengths; optical modes; peak index change; planar waveguide; static electric field; symmetrically perturbed directional couplers; test chips; three-layer structure; widened X modulators; Buffer layers; Dielectric constant; Electrooptical waveguides; Finite element methods; Optical buffering; Optical modulation; Optical refraction; Optical waveguides; Testing; Waveguide transitions;

fLanguage

English

Journal_Title

Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

0018-9197

Type

jour

DOI

10.1109/3.199255

Filename

199255