Accession Number : ADP008073

Title :   Strain Induced Optical Waveguiding and Polarization Conversion in Ferroelectric Substrates,

Corporate Author : TEXAS A AND M UNIV COLLEGE STATION DEPT OF ELECTRICAL ENGINEERING

Personal Author(s) : Eknoyan, O. ; Taylor, H. F. ; Tang, Z. ; Swenson, V. P. ; Marx, J. M.

Report Date : APR 1992

Pagination or Media Count : 2

Abstract : A localized increase in the refractive index of ferroelectric crystals has been accomplished by the use of static strain induced from a surface film. The technique does not require alteration of substrate composition by diffusion or ion exchange. Optical waveguides have been produced by this method in LiNbO3, LiTaO3 and BaTiO3. This represents the first formation of waveguides in BaTiO3, which is ideally suited for making compact low-voltage polarization control guided-wave devices and optical filters due to its large r51 electrooptic coefficient. To produce an index increase, a thick film of SiO2 is deposited on the substrate surface at an elevated temperature then cooled to room temperature and patterned. The static strain resulting from the large thermal expansion mismatch between the substrate and film causes a localized index increase in the crystal beneath regions from which the SiO2 is removed, via the strain optic effect.

Descriptors :   *FERROELECTRIC CRYSTALS, *OPTICAL WAVEGUIDES, *FIBER OPTICS, COEFFICIENTS, DIFFUSION, ELECTROOPTICS, EXPANSION, FILTERS, INDEXES, ION EXCHANGE, IONS, LOW VOLTAGE, OPTICAL FILTERS, OPTICS, POLARIZATION, REFRACTIVE INDEX, ROOM TEMPERATURE, SUBSTRATES, SURFACES, TEMPERATURE, THERMAL EXPANSION, THICK FILMS, VOLTAGE, LITHIUM TANTALATES, LITHIUM NIOBATES, SILICON DIOXIDE.

Subject Categories : Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE