Intensity noise reduction using phase-amplitude coupling in a DFB diode laser
Résumé
We present a detailed investigation of the intensity and phase noise current dependence of a DFB laser diode emitting at 1.3 μm. Phase-amplitude correlations due to the linewidth enhancement factor α are taken into account. The phase to amplitude conversion is realized with a Michelson interferometer. We show that the phase–amplitude correlation is effective only just above threshold and that it goes to zero for increasing current as predicted theoretically by Karlsson and Björk. Our experimental results are well fitted by the standard quantum noise theory of semiconductor lasers providing an additional pumping noise is added.