Diode-laser absorption spectroscopy for measurements of temperature and H_2O mole fraction by scanned-wavelength method and fixed-wavelength method has been applied to monitoring of exhaust from swirl-stabilized turbulent combustor for the detection of high frequency combustion oscillation and noise. The fluctuations of temperature and H_2O mole fraction were detected by scanned-wavelength method, and peak frequencies of power spectra of these quantities coincide with those of pressure fluctuation in the combustor. Furthermore, under the control by secondary fuel injection, the energy at peak frequency of power spectra of temperature and H_2O mole fraction decreases in accordance with noise reduction. As for the fixed-wavelength method, similar results were obtained. These results suggest that the diode-laser absorption sensor is a strong candidate for sensors for the active controls of turbulent combustion.