  This work reports on setup, characterisation and data processing of a true
quantum random number generator. As a randomness source a pure quantum vacuum
state of light is used, which is amplified by a laser beam. Performance and
behaviour of the system as well as parasitic errors are investigated. For an
optimized exploitation of the data they are Fourier-transformed and processed
further as frequency amplitudes. The extractable entropy in that data is
calculated to allow for elimination of non-random signal contributions by
hashing. The system is able to produce true and unique random numbers at a rate
of 25 Gbit/s and thus outperforms previous implementations considerably.
