Abstract: A method and apparatus are provided for in situ protection of sensitive optical materials from alternation or damage due to exposure to trace atmospheric components, during shipping, storage or operation. The sensitive optical material is disposed within an enclosure adaptable to be substantially sealed against the external atmosphere. A container, enclosing a sink material absorbing trace atmospheric components, is coupled to the enclosure by a gas permeable surface, which allows fast diffusion of the trace atmospheric component inside the enclosure to the sink material.

Abstract: A method and apparatus are provided for in situ protection of sensitive optical materials from alteration or damage due to exposure to trace atmospheric components, during shipping, storage or operation. The sensitive optical material is disposed within an enclosure adaptable to be substantially sealed against the external atmosphere. A container, enclosing a sink material absorbing trace atmospheric components, is coupled to the enclosure by a gas permeable surface, which allows fast diffusion of the trace atmospheric components present inside the enclosure to the sink material.

Abstract: A method and apparatus for determining the concentration of a substance of interest by gas-coupled photoacoustic spectroscopy (GC-PAS) with an essentially monochromatic beam of radiation in an optical portion of the electromagnetic spectrum; the radiation is selected so as to be absorbed by the substance of interest and the beam is modulated at a sonic frequency which is sufficiently high for generating a primary signal that depends upon the absorption coefficient of the substance of interest as well as upon parameters of operating the method; in order to compensate for these operating parameters, the beam is additionally modulated at a sonic frequency which is sufficiently low for generating a secondary signal which does not depend upon the absorption coefficient of the substance of interest, but, depends only upon parameters of operating the method; a ratio of the first and the second signal is obtained to generate a compensated signal for determining the concentration of the substance of interest.

Abstract: The present invention concerns a method and a device for measuring polarization dispersion of an optical fiber which is particularly useful in telecommunications, and which has a finer resolution of this measurement in comparison to methods and devices known in the art. The device consists of an interferometer (51), a low coherent light source (16), a detector (25) for generating an interferogram, and a module (52) connected in series with the optical fiber to be measured (20), this module comprising a high dispersion birefringent fiber (53) of stable, known polarization, two pairs of fiber bundles (55, 56) for adjusting the polarization controller (54) and for aligning the principal polarization modes of the optical fiber to be measured and the birefringent fiber, and an electronic processor (21) for measuring the separation of the lateral peaks on the interferogram resulting as a function of predetermined adjustments to the polarization controller.