Multi-component trace gas online detection device and method based on wavelength division multiplexing technology

The invention provides a multi-component trace gas on-line body detection device and method based on a wavelength division multiplexing technology, to-be-detected gas containing m components is introduced into a ring-down cavity, a laser control center controls m tunable lasers to emit laser signals with the wavelength of [lambda]m, multiple paths of laser signals are synthesized into a beam of laser signal after passing through a combiner, the combined laser signal is divided into two laser signals with the energy ratio of 99:1 by a light beam splitter, the laser signal with 99% of energy is transmitted to an optical isolator through a polarization maintaining optical fiber, and the laser signal with 99% of energy is transmitted to a wave splitter after passing through the optical isolator; the central data processing and control center enables multiple paths of laser signals subjected to wave separation by the wave separator to sequentially pass through according to a specific frequency, and after being col