Spatial anisotropy of linear electro-optic effect in crystal materials: II. Indicative surfaces as efficient tool for electro-optic coupling optimization in LiNbO3

• Published in: Optics and lasers in engineering 2009, Vol.47 (1), p.24-30
• Main Authors: ANDRUSHCHAK, A. S, MYTSYK, B. G, DEMYANYSHYN, N. M, KAIDAN, M. V, YURKEVYCH, O. V, DUMYCH, S. S, KITYK, A. V, SCHRANZ, W
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Nonlinear optical crystals; Optical materials; Optics; Physics
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2008.08.007

The electro-optic (EO) properties of pure and MgO-doped LiNbO3 crystals are characterized by indicative surfaces (IS) describing the spatial anisotropy of the longitudinal and transverse linear EO effects. By analyzing the IS and their stereographic projections, we have determined the geometries with maximum EO coupling. The maximum magnitudes of the linear EO effect are revealed in the longitudinal and transverse geometries along the directions that substantially deviate from the principal crystallographic axes of both crystals. Spatial analysis of the IS thus yields a set of the optimized sample geometries recommended for designers who develop EO modulators or deflectors. Just by switching from the standard cell geometry to the optimized cell geometry, as determined in the present work, one may improve almost three times the modulation efficiency of EO devices based on lithium niobate crystals. This results in a corresponding reduction of their driving voltages being evidently of great practical importance for many applications.