The DC current-voltage characteristics induced Ly a driving electric field with frequency Omega of a one-dimensional electron channel with a tunnel barrier is calculated. Electron-electron interaction of finite range is taken into account. For intermediate interaction strengths, the non-linear differential conductance shows cusp-like minima at bias voltages m (h) over bar Omega/e (m integer) that are a consequence of the finite non-zero range of the interaction but are independent of the shape of the driving electric field. However, the frequency-scaling of the photo-induced current shows a cross-over between Omega(-1) and Omega(-2), and depends on the spatial shape of the driving field and the range of the interaction.