Emission State Hierarchy Governed Coherence and Intensity Noise Properties of Quantum Dot Superluminescent Diodes

There is an inherent link between the coherence properties in the first and second order, depending on the quantum optical characteristics of the light emitting source. Whereas the coherence in the first order reflects the spectral distribution of radiation, the coherence in the second order describes the intensity fluctuations of photonic beams quantified by the relative intensity noise. In this paper, we demonstrate how the particularly interesting and highly complex spectral emission state hierarchy of a quasi-zero-dimensional inhomogeneously broadened quantum dot superluminescent diode governs both the coherence and intensity noise properties. We confirm that indeed a generalized Hodara formula reflecting the pure thermal emission character of the investigated quantum dot superluminescent diode quantitatively explains the experimentally observed complex intensity noise behavior just by the observed complex spectral behavior.