A fiber bundle has been designed for measurement of gas concentrations in a chemical vapor deposition (CVD) chamber. The bundle is broadband, covering the spectrum range from 500 to 6000 cm<sup>−1</sup>. Using this bundle, we have designed Fourier Transform infrared (FTIR) sampling configurations with reduced beam divergence (from 0.4 to 0.1 rad) and focal spot diameters (from 12 to 4 mm). The FTIR spectrum of tetraethoxysilane vapors in a CVD chamber was determined with the bundle and modified SAM connectors. An ellipsoid reflector was designed that yielded improved signal-to-noise ratios (SNR’s) in the fiber-based spectra by a factor of 2. The incorporation of this reflector in spectrometers by use of the fiber bundle has the potential to reduce the sampling times for spectra while retaining acceptable SNR’s.
© 2000 Optical Society of America
(060.2280) Fiber optics and optical communications : Fiber design and fabrication
(060.2390) Fiber optics and optical communications : Fiber optics, infrared
(230.4040) Optical devices : Mirrors
(260.3060) Physical optics : Infrared
(300.6300) Spectroscopy : Spectroscopy, Fourier transforms
Ping Lu, Xiaoyi Bao, Tom Whidden, and Sun Young Lee, "Application of a Mid-Infrared Fiber Bundle in Remote Measurement of Gas Concentrations in a Chemical Vapor Deposition Chamber," Appl. Opt. 39, 1112-1117 (2000)