An operating value of a first laser parameter of a laser device in a laser absorption spectrometer is optimized. The wavelength of laser device emitted light is adjusted by the first or a second laser parameter. The laser absorption spectrometer comprises a light intensity detector measuring the laser light intensity from the laser device. For each of multiple values of the first laser parameter: the light intensity detector measures light intensity obtained across a range of second laser parameter values, and an extremum in the light intensity measure and a peak position for the extremum are identified. A range of first laser parameter values is identified within the values of the first laser parameter for which there is a continuous trend in changes to the identified peak position with changes to the first laser parameter. The first laser parameter operating value is set to be within the identified range.