Tunable Diode Laser with a Short Tandem External Cavity

A short external cavity (EC) providing a single frequency lasing of quantum-well diode lasers with broad optical gain profiles has been developed. A feature of the proposed EC is the use of a resonant reflector formed by two thin (with thickness of approximately 100 µm) cover glasses as a return mirror. The HL8338MG laser equipped with a similar short EC made it possible to demonstrate the continuous optical frequency tuning within 100 GHz and discrete wavelength tuning in the 12.3 nm range with an output power of approximately 20 mW. The applicability of such a tunable diode laser source for gas spectroscopy was confirmed by the observation of three krypton absorption lines near 829 nm in a low-pressure radio frequency discharge.