  We analyze the statistics of photons originating from amplified spontaneous
emission generated by a quantum dot superluminescent diode. Experimentally
detectable emission properties are taken into account by parametrizing the
corresponding quantum state as a multi-mode phase-randomized Gaussian density
operator. The validity of this model is proven in two subsequent experiments
using fast two-photon-absorption detection observing second order equal-time-
as well as second order fully time-resolved intensity correlations on
femtosecond timescales. In the first experiment, we study the photon statistics
when the number of contributing longitudinal modes is systematically reduced by
applying well-controlled optical feedback. In a second experiment, we add
coherent light from a single-mode laserdiode to quantum dot superluminescent
diode broadband radiation. Tuning the power ratio, we realize tailored second
order correlations ranging from Gaussian to Poissonian statistics. Both
experiments are very well matched by theory, thus giving first insights into
quantum properties of radiation from quantum dot superluminescent diodes.
