We present the construction of an external cavity laser (ECL) diode using an InP semiconductor gain chip and a fibre Bragg grating (FBG), designed to have an emission wavelength that coincides with an absorption line of methane, to be used for spectroscopic gas sensing. The FBG was employed as a wavelength selective and feedback element, which will potentially provide the laser with wavelength tuning capability. Narrow linewidth lasing output of less than 5 MHz was achieved. To our knowledge, this is the first FBG based ECL in the 1.65 µm region.
Tunable distributed feedback (DFB) lasing output based on reflection grating configuration instead of the traditional
transmission grating type was realized from rhodamine 6G (R6G)-doped ethanol and DCM-doped methanol. Pure gain
coupling and additional index coupling were obtained in R6G-doped ethanol and DCM-doped methanol, respectively.
The tuning which was independent on the refractive index of the lasing media went through all of the tuning data for the
two cases. Dual-peak lasing emissions indicative of the existence of the index grating from the DCM-doped methanol
were observed. The interval between the dual peaks increased as the increasing of the pump energy. The effect can be
used to estimate the resonant nonlinear refractive index of luminescent materials.