The induced frequency chirping of switched pulses in an interferometri
c all-optical switch that uses pump-induced nonlinear phase shifts is
investigated. Using a nonlinear fiber Sagnac interferometer switch, it
is shown that switched pulses suffer from frequency shift and broaden
ing and can be compressed by using an anomalous group-velocity-dispers
ion fiber. It is also demonstrated that picosecond probe pulses can be
switched while retaining their temporal and spectral profiles if pump
-probe walk-off is employed.