GaAs-Al/x/Ga/1-x/As strip buried heterostructure lasers

The strip buried heterostructure (SBH) laser, which uses a thin active p-GaAs strip grown on an N-Al(x)Ga(1-x)As (x = 0.1 to 0.2) planar layer, is described, theoretically analyzed, and experimentally characterized under pulsed and continuous wave (CW) operation. The effective refractive index approximation was used to analyze the waveguiding properties and laser threshold conditions of SBH lasers; results were found to be in good agreement with experiment. For lasers with 10 and 15 micron active strips, pulsed output powers up to 400 and 230 mW/mirror without AR coating were measured at current injection levels 10 and 15 times threshold, respectively; excellent linearity and symmetry in L-I characteristics and stable transverse mode operation were observed. With efficient lateral current confinement, pulsed and CW current thresholds of about 74 and 85 mA were measured for lasers with active strips of 380 by 10 by 0.2 microns. Stable fundamental transverse mode oscillation in both directions was observed up to 9 times threshold in diodes with strip widths of about 5 microns. Individual lasers in densely packed monolithic linear arrays with center-to-center spacing of 15 microns displayed excellent uniformity of characteristics.