Patent ID: 7005645

Claim:
An apparatus for simultaneous detection of X gas species through laser radiation attenuation techniques, where at least one of the X gas species has a spectral absorption band whose wavelength is shorter than the cutoff wavelength for the other spectral absorption band, the apparatus comprising: a) N laser sources, wherein each of the N laser sources is adapted to operate at a wavelength λ N in a spectral absorption band separated by the cutoff wavelength for single mode transmission, each laser source corresponding to a spectral region for detecting a gas species; b) each of the N laser sources adapted to transmit radiation through an optical fiber constructed and arranged to provide single-mode transmission with minimal power loss to a beam splitter[BV1], said beam splitter sending a first portion of each of the N laser's radiation to a balanced ratiometric detector, and a second portion to a compound ferrule; c) the compound ferrule constructed and arranged so that each single-mode optical fiber terminating therein is held at a separation distance substantially less than a focal length of a collimating optical component to which the N beams are directed by the compound ferrule, the collimating optical component adapted to route N collimated laser beams through a process containing N gas species to be detected; and d) means for receiving and detecting nonabsorbed radiation from each laser and creating N outputs for each laser wavelength λ N .