Accession Number : ADA321128
Title : Novel Optical Fibers and Devices.
Descriptive Note : Final rept.,
Corporate Author : BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING
Personal Author(s) : Morse, T. F.
PDF Url : ADA321128
Report Date : DEC 1996
Pagination or Media Count : 15
Abstract : We have engaged in the development of gas and liquid sensors using the technique of intra-cavity laser spectroscopy. When the gain is spoiled by placing an absorber within a laser cavity, and the absorption signature corresponds to the lasing line, significant enhancements of absorption occur. As a consequence of the high reflectivity of the cavity, photons make many passes before exiting the cavity, and the effective absorption length of the cell within the cavity is significantly increased. In addition, modal considerations can further enhance the sensitivity of such measurements, so that the effective length of the cavity is increased by many orders of magnitude. Such experiments are usually carried out in a laboratory environment. By taking advantage of recent advances in fiber lasers and fiber Bragg gratings, it is possible to obtain spectroscopic accuracy in a device the size of a fountain pen. This is done by placing an absorption cell within a fiber laser cavity and compression tuning the Bragg grating that defines he cavity. This is a narrow band instrument that depends on the existence of an absorption signature under the gain bandwidth of the fiber laser. Preliminary experiments have been carried out using acetylene.
Descriptors : *FIBER OPTICS, *LASER CAVITIES, LASER PUMPING, OPTICAL SIGNATURES, GRATINGS(SPECTRA), ABSORPTION SPECTRA, REFLECTIVITY, GAS LASERS, OPTICAL DETECTORS, LASER MIRRORS, DIODE LASERS.
Subject Categories : Lasers and Masers
Fiber Optics and Integrated Optics
Distribution Statement : APPROVED FOR PUBLIC RELEASE