Optical Waveguide Scattering Reduction.
Abstract
The goal of this program was the reduction of scattering in optical waveguides to levels commensurate with the required performance characteristics of an integrated optical acoustooptic spectrum analyzer. Waveguides formed by thermal diffusion of Ti films into LiNb03 substrates were emphasized. The best waveguides were obtained by diffusing thin (< or = 280 A) Ti films or by polishing waveguides made from thicker films to reduce surface contamination believed to be associated with Li-Ti-0 compound formation. Residual scattering in the best waveguides is found to be strongly anisotropic and polarization dependent. Additionally, it can be enhanced by an applied electric field, but not by the photorefractive generation of optical damage using a beam propagating parallel to the optical axis. Possible sources of residual scattering that were considered are antiphase microdomains, separated crystalline phases, and diffused-film imperfections. None of these could be definitely identified as the source of residual scattering in good Ti:LiNbO3 waveguides; however, only the micro-domains hypothesis appears to be ruled out on the basis of its conflicts with various data. Theoretical understanding of the scattering process was extended during the program to account for the two-and three-dimensional nature of waveguide scatters, and to account for volume as well as surface-roughness scattering centers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1979
- Accession Number
- ADA082357
Entities
People
- David W. Vahey
Organizations
- Battelle Memorial Institute