Technique for measurement of the gain spectra of semiconductor diode lasers

A simple technique for determining the gain spectra of semiconductor lasers from measurements of the emission spectra of the laser is presented. The technique is insensitive to the response function of the device used to determine the emission spectra of the laser. Accurate estimates of the gain can be obtained from data which have been convolved with an instrument response function of ≲0.5 Å FWHM for a cavity free spectral range of 2.5 Å. Two applications of the gain data obtained by the technique are presented.