Linewidth measurements of tunable diode lasers using heterodyne and etalon techniques.

Measurements of the linewidths of Pb-salt diode lasers operating in the 8- and 9-microm region are reported. The linewidths of the 9-microm lasers were determined by conventional heterodyne techniques, while for the 8-microm lasers a new technique based on a Fabry-Perot etalon was used. The new technique avoids the complexity and limited wavelength range of the heterodyne measurements and can be used for any tunable laser. The linewidths …