NARROW-LINEWIDTH, TUNABLE TM3-DOPED FLUORIDE FIBER LASER FOR OPTICAL-BASED HYDROCARBON-GAS SENSING()

Operation of an efficient continuous-wave (CW) thulium-doped fiber las er emitting at wavelength, lambda = 2.31 mu m is reported, The fiber l aser parameters are optimized with a view to ultimately producing a co mpact and efficient laser source for optical absorption based gas sens ing, A number of fiber laser configurations are investigated to assess their suitability for narrow linewidth, tunable fiber laser operation emitting around lambda = 2.3 mu m, which is a wavelength region of si gnificant importance for hydrocarbon gas monitoring, Tuning ranges of 140 nm and linewidths of less than 210 MHz have been demonstrated with lasers with bulk external tuning grating, Preliminary hydrocarbon gas sensing investigation confirm the potential of this source for detect ion of ppb gas concentrations.