A new monolithic composite-cavity (GaAl)As laser

A new monolithic composite-cavity (GaAl)As laser with buried twin-ridge substrate structure offering an index-guiding operation is reported. This construction, featuring a rear facet and a reflector separated by a small air gap, is obtained by applying a new chemical etching technique. A stable single longitudinal mode is kept over a wide range of the current level. No mode jump in the lasing wavelength is observed over a wide temperature range from 15 to 40 C. Automatic power control operation is achieved with the aid of the reflector, which is also used as a photodetector providing excellent output power stability.