Gain saturation in traveling-wave semiconductor optical amplifiers

摘要

The gain saturation behavior of semiconductor traveling-wavenoptical amplifiers has been analyzed using a model that includes thenspecific dependence of gain on carrier concentration. Under thencondition of a specific gain at a particular current, it is found thatnthe saturation power strongly depends on the choice between quantum welln(QW) or bulk amplifying medium but weakly on the detailed design of thendevice such as the number of QW's or the thickness of the bulk layer.nThe higher saturation power of the QW-based amplifier is caused by itsnlogarithmic gain-current relation rather than its low opticalnconfinement factor. Also, when the unsaturated device gain is specified,nthe designed saturation power can be obtained with the lowest drivencurrent by using the highest optical confinement