Edge-emitting semiconductor microlasers with ultrashort-cavity and dry-etched high-reflectivity photonic microstructure mirrors

We demonstrate very compact low-threshold edge-emitting semiconductor lasers operating at a wavelength of 980 nm, in which periodic microstructure mirrors have been formed at both cavity ends by deep reactive ion etching. From a threshold analysis, we determined reflectivities of similar to 95% for the seven-period back reflector and similar to 80% for the three-period front mirror. Lasing has been achieved from 20-mum-long and 8-mum-wide devices exhibiting a current threshold of 7 mA. These are among the shortest in-plane electrically pumped lasers demonstrated so far, State-of-the-art electron beam lithography (EBL) and high-aspect ratio reactive ion etching (RIE) have been used for device fabrication.