Focus on the development of Tunable Diode Laser Absorption Spectroscopy(TDLAS) based sensor for measuremen tof temperature and composition in high temperature environment. Wavelength tunable DFB diode lasers are used to target the absorption features of common conbustion products like H2O, O2, CH4. Quantitative measurements of flame temperature has been carried out on standrd flat flame CH4-Air burner (McKenna)