Gas-self-filter-based erbium-doped fiber loop laser for gas detection

Abstract

An erbium-doped fiber (EDF) loop laser, based on a gas-self-filter (GSF), is developed with single or multiple wavelength emission. The GSF is a type of Mach-Zehnder interferometer with a gas cell in one arm. By matching the destructive wavelength of the interferometer with the gas absorption line, the self-filtering function is achieved. A GSF-based multi-wavelength laser with a side-mode suppression ratio of ~50 dB is performed. As an example, C₂H₂ gas is detected using a single-wavelength GSF-based laser with correlation spectroscopy, and a good linearity of the measurement is obtained. The present laser has the potential advantage for multiple gas detection, e.g., being free of wavelength calibration.