  We experimentally demonstrate a source of nearly pure single photons in
arbitrary temporal shapes heralded from a parametric down-conversion (PDC)
source at telecom wavelengths. The technology is enabled by the tailored
dispersion of in-house fabricated waveguides with shaped pump pulses to
directly generate the PDC photons in on-demand temporal shapes. We generate PDC
photons in Hermite-Gauss and frequency-binned modes and confirm a minimum
purity of 0.81, even for complex temporal shapes.
