  The temporal Talbot effect supports the generation of RF signals with high
purity in optical domain. This allows for example a remote RF generation
without the need for costly high-end electronic circuits and resource sharing.
However, one of the most interesting features of the approach is its inherent
ability to suppress phase noise during the carrier generation process. Besides
the comb laser source, the dispersive element is the key component in this
upconversion scheme. Ideally, it provides the right amount of dispersion over
the whole spectral range of the comb. Broader combs are expected to allow a
higher degree of phase noise suppression. The simulation of phase noise of an
RF tone generated by an optical scheme is challenging in terms of computational
and memory effort. Therefore, a simulation tool taking advantage of the
properties of the comb and the Talbot effect had to be developed. In this
paper, the dependency of the phase noise suppression on the dispersion
characteristic is investigated yielding an important input to the design of
these elements. First, the implemented simulation tool and the simulation
parameters ensuring a correct estimation of the phase noise before and after
dispersion influence are introduced. Then, the effect of different dispersion
characteristics on the phase noise behavior is analyzed. It could be shown and
explained how the phase noise at different offset frequencies to the carrier is
affected differently depending on the dispersion characteristic and also the
comb width. Design rules for the required comb width as well as the acceptable
variation of the produced dispersion from the ideal value depending on the
demands for the phase noise improvements could be developed and will be
presented.
