An integrated light source with a multi quantum well - diode lasers 1 / modulator

摘要

PURPOSE: To allow high-speed modulation while reducing an insertion loss by thinning the layer thickness of a barrier layer of a multiplex quantum well structure of an optical modulator part to an extent of causing combination of quantum levels. ;CONSTITUTION: Since an LD part has a large thickness of a barrier layer 2 and an independent quantum level 5, however, a modulator part has a thin thickness of a barrier layer 4 so as to become a combination quantum well due to overlapping of a wave function so as to form minibands 7. When an electric field is impressed on the modulator part, a potential difference is generated between the quantum levels of the respective quantum wells so as to become uncombined quantum wells (non-combined quantum wells). At this time a sufficient extinction characteristic can be obtained due to a quantum confinement Stark effect(QCSE). On the other hand, in the case of crossing an electric field, it becomes the combined quantum well so that a large number of carriers generated by absorption quickly disperse through the minibands 7, thus allowing modulation according to a modulation electric field.;COPYRIGHT: (C)1994,JPO