ON DISTRIBUTED MICROWAVE EFFECTS IN SEMICONDUCTOR-LASERS AND THEIR PRACTICAL IMPLICATIONS

Recently, it has been shown that when a semiconductor laser is directl y modulated at high frequencies, the modulation signals suffer substan tial loss and phase shift propagating from the wire feed point along t he length of the laser. It was suggested that these distributed microw ave effects lead to a further bandwidth degradation in electrical curr ent injection over the single-pole roll-off predicted by a lumped RC m odel. We show, however, that this degradation is significant only when the laser is driven directly by a voltage source. In contrast, when t he laser is driven, commonly, through a 50 Omega transmission line the degradation is minimal, and the total injection current is still RC l imited. (C) 1995 American Institute of Physics.