  We theoretically and experimentally investigate the design of an all-optical
noiseless magnification and sampling function free from any active gain medium
and associated high-power continuous wave pump source. The proposed technique
is based on the co-propagation of an arbitrary shaped signal together with an
orthogonally polarized intense fast sinusoidal beating within a normally
dispersive optical fiber. Basically, the strong nonlinear phase shift induced
by the sinusoidal pump beam on the orthogonal weak signal through cross-phase
modulation turns the defocusing regime into localized temporal focusing
effects. This periodic focusing is then responsible for the generation of a
high-repetition-rate temporal comb upon the incident signal whose amplitude is
directly proportional to its initial shape. This internal redistribution of
energy leads to a simultaneous sampling and magnification of the signal
intensity profile. This process allows us to experimentally demonstrate a
40-GHz sampling operation as well as an 8-dB magnification of an arbitrary
shaped nanosecond signal around 1550 nm in a 5-km long normally dispersive
fiber. The experimental observations are in quantitative agreement with
numerical and theoretical analysis.
