Problems of the precision measurements of spectral line parameters by diode
-laser spectroscopic methods were examined. The instrumental function of a
diode laser spectrometer was investigated in detail. The knowledge of the l
atter makes it possible to solve correctly the problem of the 'optical zero
' and to reconstruct the true line profile with an error less than 1%. The
instrumental function of a diode laser spectrometer was determined for the
example of a laser diode emitting radiation at the wavelength lambda = 1.53
mu m. The function represents the convolution of two Lorentzian functions
with the characteristic half-widths Delta v(1) and Delta g, which vary not
only from mode to mode but also within the limits of a single radiation mod
e.