Infrared Fibre Ring Laser for Spectroscopic Application of Gas Molecules

摘要

We fabricated erbium-doped fiber ring laser with a new structure that can operate in C- & L-band wavelength region in the optical communication band. We performed the absorption spectroscopy of acetylene (~(13)C_2H_2) and hydrogen cyanide (H~(13)C~(14)N) by using a low noise erbium-doped fiber ring laser and measured absorption spectra of more than fifty transition lines of these gases with an excellent signal to noise ratio (SNR). The wavelength of this laser can be continuously tuned over 102 nm by insertion of the fiber Fabry-Perot tunable filter (FFP-TF) in the ring cavity with a novel cavity structure and the optimal gain medium length. The acetylene cell and the hydrogen cyanide cells were fabricated with gas pressure of 120 torr and 250 torr and length of 5 cm and 15 cm, respectively. The pressure broadening coefficients of acetylene transition lines are obtained using this fiber ring laser and an external cavity laser diode.