A pulsed mid-infrared pump at $\lambda =2173\mathrm{nm}$ is used to demonstrate wideband optical parametric gain in a low-loss $2\mathrm{cm}$ long silicon photonic wire. Using dispersion engineering to obtain negative second-order ( ${\beta }_2$ ) and positive fourth-order ( ${\beta }_4$ ) dispersion, we generate broadband modulation instability and parametric fluorescence extending from $1911\mathrm{nm}–2486\mathrm{nm}$ . Using a cw probe signal to interrogate the modulation instability spectrum, we demonstrate parametric amplification $>40\mathrm{dB}$ with an on-chip gain bandwidth wider than $580\mathrm{nm}$ , as well as narrowband Raman-assisted peak gain $>50\mathrm{dB}$ .