LOW-CURRENT-THRESHOLD STRIP-BURIED-HETEROSTRUCTURE LASERS WITH SELF-ALIGNED CURRENT INJECTION STRIPES

A modified strip-buried-heterostructure (SBH) laser is described where the LPE growth process self-aligns the current-confining stripes with the active GaAs strips. With these lasers current thresholds have been reduced from ∼180 mA in previous SBH laser to ∼70 mA for active GaAs strips of 380×10×0.2 μm. Excellent linearity in light-current characteristics and symmetry in laser output from both mirrors were obtained under both pulsed and cw operations. cw operation has been achieved at heat-sink temperature as high as 115°C. The current thresholds Ith have an exponential variation with temperature of the form Ith∝exp(T/ T0) where T0 was 110°K. Relaxation oscillation and self-pulsation was not observed for lasers with clean transverse modes in pulsed response up to current injection levels as high as 4Ith.