MODE REDUCTION, Q-LOSS, GAIN SATURATION, AND BANDFILLING MODIFICATIONOF THE LIGHT VERSUS CURRENT CHARACTERISTICS OF THIN (SIMILAR-TO-0.9-MU-M) QUANTUM-WELL HETEROSTRUCTURE LASERS

Data are presented demonstrating the effect that cavity length, and th us Q, has upon quantum well heterostructure edge-emitting laser diodes that are reduced to microcavity thickness. The lasers, with reduced m ode density and enhanced spontaneous emission, are defined vertically by a Ag top-contact mirror and a closely spaced (similar to 0.9 mu m) high-contrast AlAs native oxide-GaAs distributed Bragg reflecting bott om mirror. For shorter and shorter diode lengths (700-->70 mu m, and s till lesser mode density) the light versus current (L-I) characteristi c below threshold is at first steeper and steeper (amplified stimulate d emission), until, at a diode length of similar to 100 mu m, the loss in Q and insufficient gain are manifest as a downward bend in the L-I curve and a shift to higher threshold current where bandfilling to a higher state (shorter wavelength) contributes more gain. (C) 1996 Amer ican Institute of Physics.