Influence of lithium niobate sublayer structure to refractive index of optical waveguides

ABSTRACT

Samples cleaning in ammonia-peroxide solution (APS) leads to increase of waveguides contrast after proton exchange comparing with the waveguides without APS cleaning. Surface and sublayer of lithium niobate was studied by optical microscopy, scanning electron microscopy and X-ray diffraction. It was detected many of multidirectional scratches on surface of lithium niobate and defective sublayer till a depth of 6 μm. These facts are important for manufacture of integrated optical circuits: repeatability, waveguide optical loss and circuit drift parameters.

KEYWORDS:

• Lithium niobate
• sublayer
• proton exchange
• defects
• refractive index
• ammonia-peroxide solution

Funding

The authors thank financial support from the Perm Ministry of Education, Grant С-26/004.2 and Russian Government Program for Development of Cooperation between the Higher School and Organizations Realizing Integrated Projects in High-Tech Area, Project No. 02.G25.31.0113.