The dependence of the characteristic temperature T 0 on the cavity length and lasing
wavelength is theoretical and experimentally analyzed. The devices are straight separate
confinement heterostructure lasers with active layer thickness of 30 and 12 nm grown by low
temperature liquid phase epitaxy. The recent observation that for very short lasers T 0 is an
increasing function of the cavity length is confirmed, and explained in terms of the threshold
current cavity length dependence. The temperature dependence of the threshold current I th …