The spectral lineshape of tunable diode laser absorption spectroscopy(TDLAS) can be used to calculate the gas temperature and pressure.The detection accuracy of spectral lineshape is affected by the laser tuning nonlinearity and modultion amplitude.Aiming at this problem,the influence of tuning nonlinearity and modultion amplitude on absorption lineshape was quantitatively analyzed based on tuning property curves of near infrared DFB laser in this paper.Then a tuning nonlinearity correction and ...