Accession Number : ADA098815
Title : Optical Waveguide Scattering Reduction. II.
Descriptive Note : Final rept. 2 Jul 79-2 Aug 80,
Corporate Author : BATTELLE COLUMBUS LABS OH
Personal Author(s) : Vahey,David W ; Hartman,Nile F ; Sherman,Rand C
Report Date : Dec 1980
Pagination or Media Count : 157
Abstract : The goal of this program was the reduction of scattering in optical waveguides to levels commensurate with 40 dB dynamic range for an integrated optical spectrum analyzer. Waveguides formed by thermal diffusion of Ti films into LiNbO3 substrates were emphasized. Nine potential sources of scattering in such waveguides were identified and discussed. Diagnostic methods and optical scattering experiments useful for studying the sources of scattering were described and experimental results for non-scattering experiments were presented. An analysis of the effects of Rayleigh, Rayleigh-Gans-Debye, and Mie scattering on spectrum analyzer dynamic range was performed. Formulas for differential scattering cross sections were derived, and parameter values for various sources of scattering were inserted to obtain estimates of spectrum-analyzer performance for each scattering mechanism. Rayleigh-Gans-Debye scattering centers from surface roughness and surface compounds (probably Li-Ti-O compounds) were found to lead to the largest predicted scattering. Experimental in-plane scattered-energy distributions were complicated by the effects of prism-enhanced scattering, which was theoretically investigated. Data were obtained using either end-fire input coupling or by comparing the scattering generated using two different input-output coupling-prism separations. The best performance achieved was consistent with scattering from either surface roughness or surface-compound formation. The performance was consistent with a spectrum-analyzer dynamic range of only 27 dB.
Descriptors : *LIGHT SCATTERING , *OPTICAL WAVEGUIDES , SCATTERING CROSS SECTIONS , SURFACE ROUGHNESS , FABRICATION , MIE SCATTERING , THERMAL DIFFUSION , TITANIUM , DOPING , TITANATES , LITHIUM NIOBATES , DYNAMIC RANGE , DISTRIBUTION FUNCTIONS , SPECTRUM ANALYZERS , POLISHING
Subject Categories : Electricity and Magnetism
Fiber Optics and Integrated Optics
Distribution Statement : APPROVED FOR PUBLIC RELEASE