TUNABLE AND EFFICIENT DIODE-PUMPED TM3-DOPED FLUORIDE FIBER LASER FORHYDROCARBON-GAS SENSING (REPRINTED FROM INTERNATIONAL-SYMPOSIUM ON OPTICAL SCIENCE, ENGINEERING AND INSTRUMENTATION, 1996)()

The operation of an efficient diode laser pumped continuous wave thuli um-doped fiber laser emitting at wavelength lambda = 2.31 mu m is repo rted. The operation of the fiber laser is optimized with a view to pro ducing a small and efficient laser source for optical absorption-based gas sensing. A 2-mW output power combined with a high slope efficienc y make this fiber laser a useful source for sensing spectroscopic-base d hydrocarbon gases that absorb around lambda = 2.3 mu m. A lower limi t of detection of 1000 ppm. meters for methane is routinely demonstrat ed using an unoptimized Fabry-Perot cavity laser system. The tunabilit y of the fiber laser has also been investigated in order to target spe cific hydrocarbon absorption features. Initial results with a diffract ion grating tuned system suggest detectivities of < 150 ppm.m may be o btained.