Simultaneous Measurement of Oxygen and Acetylene using a Single DFB Laser in Conjunction with Wavelength Conversion

Abstract

Measurement system using conventional optical devices using a laser of 1520nm and its second harmonic generated (SHG) beam of 760nm for simultaneous measurement of oxygen and acetylene is described. A SHG light of 760nm with an output power of 1.8mW is generated by the PPLN module and combined with a DFB laser. A single spectrum which two absorption spectra of each gas are superimposed with each other is measured in a single wavelength scan. Signal intensity of the 2^nd derivative absorption spectrum varies with the wavelength modulation width and a high signal intensity of the absorption was observed with modulation width of 7.4GHz when two gases are measured simultaneously.