  The growing requirement for photon pairs with specific spectral correlations
in quantum optics experiments has created a demand for fast, high resolution
and accurate source characterization. A promising tool for such
characterization uses the classical stimulated process, in which an additional
seed laser stimulates photon generation yielding much higher count rates, as
recently demonstrated for a $\chi^{(2)}$ integrated source in A.~Eckstein
\emph{et al.}, Laser Photon. Rev. \textbf{8}, L76 (2014). In this work we
extend these results to $\chi^{(3)}$ sources, demonstrating spectral
correlation measurements via stimulated four-wave mixing for the first time in
a integrated optical waveguide, namely a silicon nanowire. We directly confirm
the speed-up due to higher count rates and demonstrate that additional
resolution can be gained when compared to traditional coincidence measurements.
As pump pulse duration can influence the degree of spectral entanglement, all
of our measurements are taken for two different pump pulse widths. This allows
us to confirm that the classical stimulated process correctly captures the
degree of spectral entanglement regardless of pump pulse duration, and cements
its place as an essential characterization method for the development of future
quantum integrated devices.
