Fabrication and Characterization of Low-Loss, Sol-Gel Planar Waveguides

Lin Yang, S. Scott Saavedra, Neal R. Armstrong, John Hayes

Research output: Contribution to journalArticle

143 Scopus citations

Abstract

Applications of planar integrated optical waveguide (IOW) technology to problems in surface spectroscopy and optical chemical sensing have been partly limited by the difficulty of producing high-quality glass IOWs. The fabrication of IOWs by the sol-gel method from methyltriethoxysilane and titanium tetrabutoxide precursors is described here. The physical, chemical, and optical properties of the films during and after high-temperature annealing were studied using a variety of analytical techniques. The results show that the catalyst used to accelerate the sol-gel reaction strongly influenced the optical quality of the IOW. HCl catalysis produced waveguides with propagation losses of ∼ 1 dB/cm, whereas in the case of SiCl4 catalysis, propagation losses were <0.2 dB/cm, a value significantly less than any previously reported for sol-gel- derived IOWs. An examination of film surface structure and morphology by scanning electron microscopy and atomic force microscopy showed that the SiCl4-catalyzed IOWs were significantly smoother and more homogeneous on a submicrometer scale than the HCl-catalyzed IOWs. The use of SiCl4 is thought to retard formation of a microheterogeneous network containing Si-rich and Ti-rich domains, which is favored with HCl catalysis and contributes to the higher observed losses.

Original languageEnglish (US)
Pages (from-to)1254-1263
Number of pages10
JournalAnalytical chemistry
Volume66
Issue number8
DOIs
StatePublished - Apr 15 1994

ASJC Scopus subject areas

  • Analytical Chemistry

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